Updated on 2024-05-21 GMT+08:00

Type Conversion Functions

Type Conversion Functions

  • cash_words(money)

    Description: Type conversion function, which converts money into text.

    Example:

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    gaussdb=# SELECT cash_words('1.23');
                cash_words
    -----------------------------------
     One dollar and twenty three cents
    (1 row)
    
  • cast(x as y [DEFAULT z ON CONVERSION ERROR][,fmt])

    Description: Converts x into the type specified by y.

    • DEFAULT z ON CONVERSION ERROR: This parameter is optional. If the attempt to convert x to type y fails, z is converted to type y by default.
    • fmt: This parameter is optional, which can be specified when y is one of the following data types:
    • int1/int2/int4/int8/int16/float4/float8/numeric: The function of the optional parameter fmt is the same as that in the to_number(expr [,fmt]) function.
    • date/timestamp/timestamp with time zone: The function of the optional parameter fmt is the same as that in the to_date(string [,fmt])/to_timestamp(string [,fmt]) /to_timestamp_tz(string [,fmt]) function.
    Example:
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    gaussdb=# SELECT cast('22-ocX-1997' as timestamp DEFAULT '22-oct-1997' ON CONVERSION ERROR, 'DD-Mon-YYYY');
          timestamp      
    ---------------------
     1997-10-22 00:00:00
    (1 row)
    

    The DEFAULT z ON CONVERSION ERROR and fmt syntaxes are supported only when a_format_version is set to 10c and a_format_dev_version is set to s1 in an ORA-compatible database.

  • hextoraw(raw)

    Description: Converts a string in hexadecimal format into binary format.

    Return type: raw

    Example:

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    gaussdb=# SELECT hextoraw('7D');
     hextoraw 
    ----------
     7D
    (1 row)
    
  • numtoday(numeric)

    Description: Converts values of the number type into the timestamp of the specified type.

    Return type: timestamp

    Example:

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    gaussdb=# SELECT numtoday(2);
     numtoday
    ----------
     2 days
    (1 row)
    
  • rawtohex(string)

    Description: Converts a string in binary format into hexadecimal format.

    The result is the ACSII code of the input characters in hexadecimal format.

    Return type: varchar

    Example:

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    gaussdb=# SELECT rawtohex('1234567');
        rawtohex    
    ----------------
     31323334353637
    (1 row)
    
  • to_blob(raw)

    Description: Converts the RAW type to the BLOB type.

    Return type: BLOB

    Example:

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    gaussdb=# SELECT to_blob('0AADD343CDBBD'::RAW(10));
        to_blob    
    ----------------
     00AADD343CDBBD
    (1 row)
    

    The to_blob function is supported only when the value of a_format_version is 10c and the value of a_format_dev_version is s2.

  • to_bigint(varchar)

    Description: Converts the character type to the bigint type.

    Return type: bigint

    Example:

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    gaussdb=# SELECT to_bigint('123364545554455');
        to_bigint    
    ----------------
     123364545554455
    (1 row)
    
  • to_binary_double(expr)

    Description: Converts an expression to a value of the float8 type.

    expr: supports the number, float4, and float8 data types and character strings that can be implicitly converted to numeric types.

    Return type: float8

    Example:

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    gaussdb=# SELECT to_binary_double('12345678');
     to_binary_double 
    ------------------
             12345678
    (1 row)
    
  • to_binary_double(expr, fmt)

    Description: Converts an expression to a value of the float8 type after format matching.

    expr/fmt: supports character strings of the char, nchar, varchar2, and nvarchar2 types. The expr also supports numeric types that can be implicitly converted to character types.

    Return type: float8

    Example:

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    gaussdb=# SELECT to_binary_double('1,2,3', '9,9,9');
     to_binary_double 
    ------------------
                  123
    (1 row)
    
  • to_binary_double(expr default return_value on conversion error)

    Description: Converts an expression to a value of the float8 type. If the conversion fails, the default value return_value is returned.

    expr: supports the number, float4, and float8 data types and numeric types that can be implicitly converted to character strings.

    Note: If expr is not of the numeric or character type, an error is reported.

    Return type: float8

    Example:

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    gaussdb=# SELECT to_binary_double(1e2 default 12 on conversion error);
     to_binary_double 
    ------------------
                  100
    (1 row)
    
    gaussdb=# SELECT to_binary_double('aa' default 12 on conversion error);
     to_binary_double 
    ------------------
                   12
    (1 row)
    
  • to_binary_double(expr default return_value on conversion error, fmt)

    Description: Converts an expression to a value of the float8 type after format matching. If the expression fails to be converted, the default value return_value is returned.

    expr/fmt: supports the char, nchar, varchar2, and nvarchar2 types. expr also supports numeric types that can be implicitly converted to character types.

    Return type: float8

    Example:

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    gaussdb=# SELECT to_binary_double('12-' default 10 on conversion error, '99S');
     to_binary_double 
    ------------------
                  -12
    (1 row)
    
    gaussdb=# SELECT to_binary_double('aa-' default 12 on conversion error, '99S');
     to_binary_double 
    ------------------
                   10
    (1 row)
    

    The to_binary_double function is supported only when the value of a_format_version is 10c and the value of a_format_dev_version is s2 in an ORA-compatible database.

  • to_binary_float(expr)

    Description: Converts an expression to a value of the float4 type.

    expr: supports the number, float4, and float8 data types and character strings that can be implicitly converted to numeric types.

    Return type: float4

    Example:

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    gaussdb=# SELECT to_binary_float('12345678');
     to_binary_float 
    ------------------
          1.23457e+07
    (1 row)
    
  • to_binary_float(expr, fmt)

    Description: Converts an expression to a value of the float4 type after format matching.

    expr/fmt: supports character strings of the char, nchar, varchar2, and nvarchar2 types. The expr also supports numeric types that can be implicitly converted to character types.

    Return type: float4

    Example:

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    gaussdb=# SELECT to_binary_float('1,2,3', '9,9,9');
     to_binary_float
    ------------------
                  123
    (1 row)
    
  • to_binary_float(expr default return_value on conversion error)

    Description: Converts an expression to a value of the float4 type. If the conversion fails, the default value return_value is returned.

    expr: supports the number, float4, and float8 data types and numeric types that can be implicitly converted to character strings.

    Note: If expr is not of the numeric or character type, an error is reported.

    Return type: float4

    Example:

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    gaussdb=# SELECT to_binary_float(1e2 default 12 on conversion error);
     to_binary_float 
    ------------------
                  100
    (1 row)
    
    gaussdb=# SELECT to_binary_float('aa' default 12 on conversion error);
     to_binary_float
    ------------------
                   12
    (1 row)
    
  • to_binary_float(expr default return_value on conversion error, fmt)

    Description: Converts an expression to a value of the float4 type after format matching. If the expression fails to be converted, the default value return_value is returned.

    expr/fmt: supports character strings of the char, nchar, varchar2, and nvarchar2 types. The expr also supports numeric types that can be implicitly converted to character types.

    Return type: float4

    Example:

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    gaussdb=# SELECT to_binary_float('12-' default 10 on conversion error, '99S');
     to_binary_float
    ------------------
                  -12
    (1 row)
    
    gaussdb=# SELECT to_binary_float('aa-' default 12 on conversion error, '99S');
     to_binary_float
    ------------------
                   10
    (1 row)
    

    The to_binary_float function is supported only when the value of a_format_version is 10c and the value of a_format_dev_version is s2 in an ORA-compatible database.

  • to_char(datetime/interval [, fmt])

    Description: Converts a DATETIME or INTERVAL value of the DATE/TIMESTAMP/TIMESTAMP WITH TIME ZONE/TIMESTAMP WITH LOCAL TIME ZONE type into the VARCHAR type according to the format specified by fmt.

    • The optional parameter fmt allows for the following types: date, time, week, quarter, and century. Each type has a unique template. The templates can be combined together. Common templates include HH, MI, SS, YYYY, MM, and DD. For details, see Table 4.
    • A template may have a modification word. FM is a common modification word and is used to suppress the preceding zero or the following blank spaces.

    Return type: varchar

    Example:

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    gaussdb=# SELECT to_char(current_timestamp,'HH12:MI:SS');
     to_char  
    ----------
     10:19:26
    (1 row)
    
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    gaussdb=# SELECT to_char(current_timestamp,'FMHH12:FMMI:FMSS');
     to_char  
    ----------
     10:19:46
    (1 row)
    
  • to_char(double precision/real, text)

    Description: Converts the values of the floating point type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_char(125.8::real, '999D99');
     to_char 
    ---------
      125.80
    (1 row)
    
  • to_char (numeric/smallint/integer/bigint/double precision/real[, fmt])

    Descriptions: Converts an integer or a value in floating point format into a string in specified format.

    • The optional parameter fmt allows for the following types: decimal point, group (thousand) separator, positive/negative sign and currency sign. Each type has a unique template. The templates can be combined together. Common templates include: 9, 0, millesimal sign (,), and decimal point (.). For details, see Table 1.
    • A template can have a modification word, similar to FM. However, FM does not suppress 0 which is output according to the template.
    • Use the template X or x to convert an integer value into a string in hexadecimal format.

    Return type: varchar

    Example:

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    gaussdb=# SELECT to_char(1485,'9,999');
     to_char 
    ---------
      1,485
    (1 row)
    
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    gaussdb=# SELECT to_char( 1148.5,'9,999.999');
      to_char   
    ------------
      1,148.500
    (1 row)
    
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    gaussdb=# SELECT to_char(148.5,'990999.909');
       to_char   
    -------------
        0148.500
    (1 row)
    
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    gaussdb=# SELECT to_char(123,'XXX');
     to_char 
    ---------
       7B
    (1 row)
    
    Table 1 fmt parameter of the number type

    Pattern

    Description

    , (comma)

    Group (thousand) separator

    . (period)

    Decimal point

    $

    $ output to the specified position

    0

    Value with leading zeros

    9

    Value with specified digits

    B

    Space returned when the integer part is 0

    C

    Currency symbol (depending on the locale setting)

    D

    Decimal point (depending on the locale setting)

    EEEE

    Scientific notation

    G

    Group separator (depending on the locale setting)

    L

    Currency symbol (depending on the locale setting)

    MI

    Minus sign in the specified position (if the number is less than 0)

    PR

    Negative values in angle brackets

    RN

    Roman numeral (ranging from 1 to 3999)

    S

    Signed number (depending on the locale setting)

    TM

    Standard number in scientific notation

    TM9

    Standard number in scientific notation

    TME

    Standard number in scientific notation

    U

    Currency symbol (depending on the locale setting)

    V

    Decimal with specified number of digits shifted

    PL

    Plus sign in the specified position (if the number is greater than 0)

    SG

    Plus or minus sign in the specified position

    TH or th

    Ordinal number suffix

    This function supports the $, C, TM, TM9, TME, and U patterns when a_format_version is set to 10c and a_format_dev_version is set to s1 in an ORA-compatible database. In addition, the fmt parameter cannot be set to TH, PL, or SG in this case.

  • to_char(interval, text)

    Description: Converts the values of the time interval type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_char(interval '15h 2m 12s', 'HH24:MI:SS');
     to_char
    ----------
     15:02:12
    (1 row)
    
  • to_char(integer, text)

    Description: Converts the values of the integer type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_char(125, '999');
     to_char
    ---------
      125
    (1 row)
    
  • to_char(set)

    Description: Converts a value of the SET type to a string. The distributed system does not support the SET data type.

    Return value: text

  • to_char(numeric, text)

    Description: Converts the values of the numeric type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_char(-125.8, '999D99S');
     to_char
    ---------
     125.80-
    (1 row)
    
  • to_char (string)

    Description: Converts the CHAR/VARCHAR/VARCHAR2/CLOB type into the VARCHAR type.

    If this function is used to convert data of the CLOB type, and the value to be converted exceeds the value range of the target type, an error is returned.

    Return type: varchar

    Example:

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    gaussdb=# SELECT to_char('01110');
     to_char
    ---------
     01110
    (1 row)
    
  • to_nvarchar2(numeric)

    Description: Converts to the nvarchar2 type.

    Parameter: numeric

    Return type: nvarchar2

  • to_char(timestamp, text)

    Description: Converts the values of the timestamp type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_char(current_timestamp, 'HH12:MI:SS');
     to_char
    ----------
     10:55:59
    (1 row)
    
    • When a_format_version is set to 10c and a_format_dev_version is set to s1, the to_char function reports an error for the incorrect format (fmt).
    • In non-compatible mode, the to_char function outputs the incorrect format (fmt) without change. For example, if the fmt is FF10, FF1 is matched for formatted output, and then 0 is output without change.
  • to_nchar (datetime/interval [, fmt])

    Description: Converts a DATETIME or INTERVAL value of the DATE/TIMESTAMP/TIMESTAMP WITH TIME ZONE/TIMESTAMP WITH LOCAL TIME ZONE type into the TEXT type according to the format specified by fmt.

    • The optional parameter fmt allows for the following types: date, time, week, quarter, and century. Each type has a unique template. The templates can be combined together. Common templates include HH, MI, SS, YYYY, MM, and DD. For details, see Table 4.
    • A template may have a modification word. FM is a common modification word and is used to suppress the preceding zero or the following blank spaces.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(current_timestamp,'HH12:MI:SS');
     to_nchar  
    ----------
     10:19:26
    (1 row)
    
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    gaussdb=# SELECT to_nchar(current_timestamp,'FMHH12:FMMI:FMSS');
     to_nchar  
    ----------
     10:19:46
    (1 row)
    
  • to_nchar(double precision/real, text)

    Description: Converts the values of the floating point type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(125.8::real, '999D99');
     to_nchar 
    ---------
      125.80
    (1 row)
    
  • to_nchar (numeric/smallint/integer/bigint/double precision/real[, fmt])

    Descriptions: Converts an integer or a value in floating point format into a string in specified format.

    • The optional parameter fmt allows for the following types: decimal point, group (thousand) separator, positive/negative sign and currency sign. Each type has a unique template. The templates can be combined together. Common templates include: 9, 0, millesimal sign (,), and decimal point (.). For details, see Table 1.
    • A template can have a modification word, similar to FM. However, FM does not suppress 0 which is output according to the template.
    • Use the template X or x to convert an integer value into a string in hexadecimal format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(1485,'9,999');
     to_nchar 
    ---------
      1,485
    (1 row)
    
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    gaussdb=# SELECT to_nchar( 1148.5,'9,999.999');
      to_nchar   
    ------------
      1,148.500
    (1 row)
    
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    gaussdb=# SELECT to_nchar(148.5,'990999.909');
       to_nchar   
    -------------
        0148.500
    (1 row)
    
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    gaussdb=# SELECT to_nchar(123,'XXX');
     to_nchar 
    ---------
       7B
    (1 row)
    

    This function supports the $, C, TM, TM9, TME, and U patterns when a_format_version is set to 10c and a_format_dev_version is set to s1 in an ORA-compatible database. In addition, the fmt parameter cannot be set to TH, PL, or SG in this case.

  • to_nchar(interval, text)

    Description: Converts the values of the time interval type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(interval '15h 2m 12s', 'HH24:MI:SS');
     to_nchar
    ----------
     15:02:12
    (1 row)
    
  • to_nchar(integer, text)

    Description: Converts the values of the integer type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(125, '999');
     to_nchar
    ---------
      125
    (1 row)
    
  • to_nchar(set)

    Description: Converts a value of the SET type to a string. The distributed system does not support the SET data type.

    Return value: text

  • to_nchar(numeric, text)

    Description: Converts the values of the numeric type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(-125.8, '999D99S');
     to_nchar
    ---------
     125.80-
    (1 row)
    
  • to_nchar (string)

    Description: Converts the CHAR/VARCHAR/VARCHAR2/CLOB type into the TEXT type.

    If this function is used to convert data of the CLOB type, and the value to be converted exceeds the value range of the target type, an error is returned.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar('01110');
     to_nchar
    ---------
     01110
    (1 row)
    
  • to_nchar(timestamp, text)

    Description: Converts the values of the timestamp type into the strings in the specified format.

    Return type: text

    Example:

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    gaussdb=# SELECT to_nchar(current_timestamp, 'HH12:MI:SS');
     to_nchar
    ----------
     10:55:59
    (1 row)
    
  • to_clob(char/nchar/varchar/varchar2/nvarchar2/text/raw)

    Description: Converts the RAW type or text character set type CHAR/NCHAR/VARCHAR/VARCHAR2/NVARCHAR2/TEXT into the CLOB type.

    Return type: CLOB

    Example:

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    gaussdb=# SELECT to_clob('ABCDEF'::RAW(10));
     to_clob 
    ---------
     ABCDEF
    (1 row)
    
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    gaussdb=# SELECT to_clob('hello111'::CHAR(15));
     to_clob  
    ----------
     hello111
    (1 row)
    
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    gaussdb=# SELECT to_clob('gauss123'::NCHAR(10));
     to_clob  
    ----------
     gauss123
    (1 row)
    
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    gaussdb=# SELECT to_clob('gauss234'::VARCHAR(10));
     to_clob  
    ----------
     gauss234
    (1 row)
    
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    gaussdb=# SELECT to_clob('gauss345'::VARCHAR2(10));
     to_clob  
    ----------
     gauss345
    (1 row)
    
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    gaussdb=# SELECT to_clob('gauss456'::NVARCHAR2(10));
     to_clob  
    ----------
     gauss456
    (1 row)
    
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    gaussdb=# SELECT to_clob('World222!'::TEXT);
      to_clob  
    -----------
     World222!
    (1 row)
    
  • to_date(text)

    Description: Converts values of the text type into the timestamp in the specified format. Currently, only the following two formats are supported:

    • Format 1: Date without separators, for example, 20150814. The value must contain the complete year, month, and day.
    • Format 2: Date with separators, for example, 2014-08-14. The separator can be any non-digit character.

    Return type: timestamp without time zone

    Example:

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    gaussdb=# SELECT to_date('2015-08-14');
           to_date
    ---------------------
     2015-08-14 00:00:00
    (1 row)
    
  • to_date(text, text)

    Description: Converts the values of the string type into the dates in the specified format.

    Return type: timestamp without time zone

    Example:

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    gaussdb=# SELECT to_date('05 Dec 2000', 'DD Mon YYYY');
           to_date
    ---------------------
     2000-12-05 00:00:00
    (1 row)
    

    Case execution environment: The value of a_format_version is 10c, the value of a_format_dev_version is s1, and the value of nls_timestamp_format is YYYY-MM-DD HH24:MI:SS.

  • to_date(text [DEFAULT return_value ON CONVERSION ERROR [, fmt]])

    Description: Converts a string text into a value of the DATE type according to the format specified by fmt. If fmt is not specified, a_format_version is set to 10c, and a_format_dev_version is set to s1, the format specified by nls_timestamp_format is used for conversion. Otherwise, the fixed format (fmt = 'yyyy-mm-dd hh24-mi-ss') is used for conversion.

    • text: any expression that can be calculated to CHAR/VARCHAR2/NCHAR/NVARCHAR2/TEXT string. If null is entered, null is returned.
    • DEFAULT return_value ON CONVERSION ERROR: This parameter is optional, which can be used to specify the return value when text fails to be converted to the DATE type. The value of return_value can be an expression or a bound variable that can be converted to the CHAR/VARCHAR2/NCHAR/NVARCHAR2/TEXT type or null. The method of converting return_value to the DATE type is the same as that of converting text to the DATE type. If return_value fails to be converted to the DATE type, an error is reported.
    • fmt: This parameter is optional, which specifies the date and time model format of text. By default, text must comply with the default date format. If fmt is set to J, text must be an integer.

    Return type: timestamp without time zone

    Example:

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    gaussdb=# SELECT to_date('2015-08-14');
           to_date
    ---------------------
     2015-08-14 00:00:00
    (1 row)
    gaussdb=# SELECT to_date('05 Dec 2000', 'DD Mon YYYY');
           to_date
    ---------------------
     2000-12-05 00:00:00
    (1 row)
    
    gaussdb=# SET a_format_version='10c';
    SET
    gaussdb=# SET a_format_dev_version='s1';
    SET
    gaussdb=# SHOW nls_timestamp_format;
        nls_timestamp_format    
    ----------------------------
     DD-Mon-YYYY HH:MI:SS.FF AM
    (1 row)
    gaussdb=# SELECT to_date('12-jan-2022' default '12-apr-2022' on conversion error);
           to_date       
    ---------------------
     2022-01-12 00:00:00
    (1 row)
    gaussdb=# SELECT to_date('12-ja-2022' default '12-apr-2022' on conversion error);
           to_date       
    ---------------------
     2022-04-12 00:00:00
    (1 row)
    gaussdb=# SELECT to_date('2022-12-12' default '2022-01-01' on conversion error, 'yyyy-mm-dd');
           to_date       
    ---------------------
     2022-12-12 00:00:00
    (1 row)
    • The DEFAULT return_value ON CONVERSION ERROR syntax is supported only when a_format_version is set to 10c and a_format_dev_version is set to s1.
    • When a_format_version is set to 10c and a_format_dev_version is set to s1, the system may not report an error if the entered year exceeds 9999. For example, the result of to_date('99999-12-12', 'yyyy-mm-dd hh24:mi:ss') is 9999-09-12 12:00:00. If the value of year exceeds 9999, the number following 9999 will be parsed as the next fmt. This restriction also applies to to_timestamp.
  • to_number ( expr [, fmt])

    Description: Converts expr into a value of the NUMBER type according to the specified format.

    For details about the type conversion formats, see Table 2.

    If a hexadecimal string is converted into a decimal number, the hexadecimal string can include a maximum of 16 bytes if it is to be converted into a sign-free number.

    During the conversion from a hexadecimal string to a decimal digit, the format string cannot have a character other than x or X. Otherwise, an error is reported.

    Return type: number

    Example:

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    gaussdb=# SELECT to_number('12,454.8-', '99G999D9S');
     to_number 
    -----------
      -12454.8
    (1 row)
    
  • to_number(text, text)

    Description: Converts the values of the string type into the numbers in the specified format.

    Return type: numeric

    Example:

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    gaussdb=# SELECT to_number('12,454.8-', '99G999D9S');
     to_number
    -----------
      -12454.8
    (1 row)
    
  • to_number(expr [DEFAULT return_value ON CONVERSION ERROR [, fmt]])

    Description: Converts a string expr to a value of the numeric type based on the format specified by fmt. If fmt is not specified, text must be a character string that can be directly converted to numeric, for example, '123', '1e2'.

    For details about the type conversion formats, see Table 3.

    • expr: an expression that can be converted into a CHAR/VARCHAR2/NCHAR/NVARCHAR2/TEXT/INT/FLOAT string. If null is entered, null is returned.
    • DEFAULT return_value ON CONVERSION ERROR: This parameter is optional, which can be used to specify the return value when expr fails to be converted to the numeric type. Similar to expr, return_value can be any type that can be converted to a character string. Similar to expr, return_value is converted based on the format specified by fmt. The system checks whether return_value fails to be converted. If return_value fails to be converted, the function reports an error.
    • fmt: This parameter is optional, which specifies the conversion format of expr.

      If any input parameter is NULL, NULL is returned.

      Return type: numeric

      Example:

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      10
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      15
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      gaussdb=# SET a_format_version='10c';
      gaussdb=# SET a_format_dev_version='s1';
      
      gaussdb=# SELECT to_number('1e2');
       to_number 
      -----------
             100
      (1 row)
      
      gaussdb=# SELECT to_number('123.456');
       to_number 
      -----------
         123.456
      (1 row)
      
      gaussdb=# SELECT to_number('123', '999');
       to_number 
      -----------
             123
      (1 row)
      
      gaussdb=# SELECT to_number('123-', '999MI');
       to_number 
      -----------
            -123
      (1 row)
      
      gaussdb=# SELECT to_number('123' default '456-' on conversion error, '999MI');
       to_number 
      -----------
            -456
      (1 row)
      

      The DEFAULT return_value ON CONVERSION ERROR syntax is supported only when a_format_version is set to 10c and a_format_dev_version is set to s1.

  • to_timestamp(double precision)

    Description: Converts a Unix century into a timestamp.

    Return type: timestamp with time zone

    Example:

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    gaussdb=# SELECT to_timestamp(1284352323);
          to_timestamp      
    ------------------------
     2010-09-13 12:32:03+08
    (1 row)
    
  • to_timestamp(string [,fmt])

    Description: Converts a string into a value of the timestamp type according to the format specified by fmt. When fmt is not specified, perform the conversion according to the format specified by nls_timestamp_format.

    In to_timestamp in GaussDB:

    • If the input year YYYY is 0, an error will be reported.
    • If the input year YYYY is less than 0, specify SYYYY in fmt. The year with the value of n (an absolute value) BC will be output correctly.

    Characters in the fmt must match the schema for formatting the data and time. Otherwise, an error is reported.

    Return type: timestamp without time zone

    Example:

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    gaussdb=# SHOW nls_timestamp_format;
        nls_timestamp_format    
    ----------------------------
     DD-Mon-YYYY HH:MI:SS.FF AM
    (1 row)
    
    gaussdb=# SELECT to_timestamp('12-sep-2014');
        to_timestamp     
    ---------------------
     2014-09-12 00:00:00
    (1 row)
    
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    gaussdb=# SELECT to_timestamp('12-Sep-10 14:10:10.123000','DD-Mon-YY HH24:MI:SS.FF');
          to_timestamp       
    -------------------------
     2010-09-12 14:10:10.123
    (1 row)
    
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    gaussdb=# SELECT to_timestamp('-1','SYYYY');
          to_timestamp      
    ------------------------
     0001-01-01 00:00:00 BC
    (1 row)
    
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    gaussdb=# SELECT to_timestamp('98','RR');
        to_timestamp     
    ---------------------
     1998-01-01 00:00:00
    (1 row)
    
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    gaussdb=# SELECT to_timestamp('01','RR');
        to_timestamp     
    ---------------------
     2001-01-01 00:00:00
    (1 row)
    
    1. When a_format_version is set to 10c and a_format_dev_version is set to s1, fmt supports FF[7-9]. When FF[7-9] is used, and the length of the corresponding position in the string is less than or equal to the number following FF, then, the number can be converted. However, the maximum length of the final conversion result is six digits.
    2. The result returned by the current_timestamp function cannot be used as a string parameter.
  • to_timestamp(text [DEFAULT return_value ON CONVERSION ERROR [, fmt]])

    Description: Converts a string text into a value of the DATE type according to the format specified by fmt. If fmt is not specified, a_format_version is set to 10c, and a_format_dev_version is set to s1, the format specified by nls_timestamp_format is used for conversion. Otherwise, the fixed format (fmt = 'yyyy-mm-dd hh24-mi-ss') is used for conversion.

    • text: any expression that can be calculated to CHAR/VARCHAR2/NCHAR/NVARCHAR2/TEXT string. If null is entered, null is returned.
    • DEFAULT return_value ON CONVERSION ERROR: This parameter is optional, which can be used to specify the return value when text fails to be converted to the DATE type. The value of return_value can be an expression or a bound variable that can be converted to the CHAR/VARCHAR2/NCHAR/NVARCHAR2/TEXT type or null. The method of converting return_value to the timestamp type is the same as that of converting text to the timestamp type. If return_value fails to be converted to the timestamp type, an error is reported.
    • fmt: This parameter is optional, which specifies the date and time model format of text. By default, text must comply with the default date format. If fmt is set to J, text must be an integer.

    Return type: timestamp without time zone

    Example:

    gaussdb=# SET a_format_version='10c';
    SET
    gaussdb=# SET a_format_dev_version='s1';
    SET
    gaussdb=# SELECT to_timestamp('11-Sep-11' DEFAULT '12-Sep-10 14:10:10.123000' ON CONVERSION ERROR,'DD-Mon-YY HH24:MI:SS.FF');
        to_timestamp     
    ---------------------
     2011-09-11 00:00:00
    (1 row)
    gaussdb=# SELECT to_timestamp('12-Sep-10 14:10:10.123000','DD-Mon-YY HH24:MI:SSXFF');
          to_timestamp       
    -------------------------
     2010-09-12 14:10:10.123
    (1 row)

    The DEFAULT return_value ON CONVERSION ERROR syntax is supported only when a_format_version is set to 10c and a_format_dev_version is set to s1.

  • to_timestamp(text, text)

    Description: Converts values of the string type into the timestamp of the specified type.

    Return type: timestamp

    Example:

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    gaussdb=# SELECT to_timestamp('05 Dec 2000', 'DD Mon YYYY');
        to_timestamp
    ---------------------
     2000-12-05 00:00:00
    (1 row)
    
  • to_timestamp_tz(text [,text])

    Description: Converts values of the string type into the timestamp of the specified type with the time zone.

    Return type: timestamp with time zone

    Example:

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    gaussdb=# SELECT to_timestamp_tz('05 Dec 2001', 'DD Mon YYYY');
        to_timestamp_tz
    --------------------------
     2001-12-05 00:00:00+08:00
    (1 row)
    

    This function is valid only when the value of a_format_version is 10c and that of a_format_dev_version is s1 in an ORA-compatible database.

  • to_timestamp_tz(string [DEFAULT return_value ON CONVERSION ERROR] [,fmt])

    Description: Converts a string into a value of the timestamp type with the time zone according to the format specified by fmt. When fmt is not specified, perform the conversion according to the format specified by nls_timestamp_tz_format.

    DEFAULT return_value ON CONVERSION ERROR: This parameter is optional. If string fails to be converted to the timestamp type with time zone, return_value is converted to the timestamp type with time zone.

    fmt: This parameter is optional, which specifies the date and time model format of string. The setting of this parameter is the same as that in the to_timestamp function.

    Return type: timestamp with time zone

    Example:

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    gaussdb=# SELECT to_timestamp_tz('05 DeX 2000' DEFAULT '05 Dec 2001' ON CONVERSION ERROR, 'DD Mon YYYY');
        to_timestamp_tz
    --------------------------
     2001-12-05 00:00:00+08:00
    (1 row)
    

    This function is valid only when the value of a_format_version is 10c and that of a_format_dev_version is s1 in an ORA-compatible database.

  • to_dsinterval(text)

    Description: Converts characters to the interval type. SQL-compatible and ISO formats are supported.

    Return type: interval

    Example:

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    gaussdb=# SELECT to_dsinterval('12 1:2:3.456');
        to_dsinterval     
    ----------------------
     12 days 01:02:03.456
    (1 row)
    
    gaussdb=# SELECT to_dsinterval('P3DT4H5M6S');
      to_dsinterval  
    -----------------
     3 days 04:05:06
    (1 row)
    

    This function is valid only when the value of a_format_version is 10c and that of a_format_dev_version is s2 in an ORA-compatible database.

  • to_yminterval(text)

    Description: Converts characters to the interval type. SQL-compatible and ISO formats are supported.

    Return type: interval

    Example:

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    gaussdb=# SELECT to_yminterval('1-1');
     to_yminterval 
    -----------------
     1 year 1 mon
    (1 row)
    
    gaussdb=# SELECT to_yminterval('P13Y3M4DT4H2M5S');
     to_yminterval  
    -----------------
     13 years 3 mons
    (1 row)
    

    This function is valid only when the value of a_format_version is 10c and that of a_format_dev_version is s2 in an ORA-compatible database.

Table 2 Template patterns for numeric formatting

Pattern

Description

9

Value with specified digits

0

Values with leading zeros

Period (.)

Decimal point

Comma (,)

Group (thousand) separator

PR

Negative values in angle brackets

S

Signed number (depending on the locale setting)

L

Currency symbol (depending on the locale setting)

D

Decimal point (depending on the locale setting)

G

Group separator (depending on the locale setting)

MI

Minus sign in the specified position (if the number is less than 0)

PL

Plus sign in the specified position (if the number is greater than 0)

SG

Plus or minus sign in the specified position

RN

Roman numeral (ranging from 1 to 3999)

TH or th

Ordinal number suffix

V

Decimal with specified number of digits shifted

x or X

Hexadecimal-to-decimal conversion identifier

Table 3 Template patterns for to_number formatting

Pattern

Description

9

Matches a digit. The number of digits "9" can be greater than or equal to that in the corresponding position in expr.

0

Strictly matches a digit. The number of digits "0" must be equal to that in expr.

5

Matches digit 0 or 5.

Period (.)

Decimal point in the specified position

Comma (,)

Group (thousand) separator in the specified position. Multiple commas can be specified in fmt.

B

No leading sign

PR

A negative value in angle brackets, or a positive value with no leading sign.

S

A negative value with the leading minus sign (–) or a positive value with the leading plus sign (+)

MI

A negative value with the leading minus sign (–) or a positive value with no leading sign

$

Leading dollar sign

L

Local currency symbol

C

Symbol of currency in the specified position (complying with the ISO standard)

U

Dual-currency symbol

D

Decimal point (uses locale)

G

Group separator (complying with the ISO standard). Multiple commas can be specified in fmt.

RN / rn

Roman numeral (ranging from 1 to 3999). to_number does not support this format.

V

to_number does not support this format.

X / x

Conversion between hexadecimal and decimal

TM

to_number does not support this format.

FM

This format can be used only at the beginning of fmt.

EEEE

Conversion based on the scientific notation model

When a_format_version is set to 10c and a_format_dev_version is set to s1, refer to this table for the setting of fmt. Otherwise, refer to the previous table. The fmt setting complying with the ISO standard is affected by the values of LC_MONETARY and LC_NUMERIC parameters.

  • cast_varchar2_to_raw_for_histogram(varchar2)

    Description: Converts from the varchar2 type to the raw type.

    Return type: raw

  • abstime_text

    Description: Converts abstime to text.

    Parameter: abstime

    Return type: text

  • abstime_to_smalldatetime

    Description: Converts abstime to smalldatatime.

    Parameter: abstime

    Return type: smalldatetime

  • bigint_tid

    Description: Converts bigint to tid.

    Parameter: bigint

    Return type: tid

  • bool_int1

    Description: Converts Boolean to int1.

    Parameter: Boolean

    Return type: tinyint

  • bool_int2

    Description: Converts Boolean to int2.

    Parameter: Boolean

    Return type: smallint

  • bool_int8

    Description: Converts Boolean to int8.

    Parameter: Boolean

    Return type: bigint

  • bpchar_date

    Description: Converts a string to a date.

    Parameter: character

    Return type: date

  • bpchar_float4

    Description: Converts a string to float4.

    Parameter: character

    Return type: real

  • bpchar_float8

    Description: Converts a string to float8.

    Parameter: character

    Return type: double precision

  • bpchar_int4

    Description: Converts a string to int4.

    Parameter: character

    Return type: integer

  • bpchar_int8

    Description: Converts a string to int8.

    Parameter: character

    Return type: bigint

  • bpchar_numeric

    Description: Converts a string to numeric.

    Parameter: character

    Return type: numeric

  • bpchar_timestamp

    Description: Converts a string to a timestamp.

    Parameter: character

    Return type: timestamp without time zone

  • bpchar_to_smalldatetime

    Description: Converts a string to smalldatetime.

    Parameter: character

    Return type: smalldatetime

  • complex_array_in

    Description: Converts the external complex_array type to the internal anyarray array type.

    Parameter: cstring, oid, int2vector

    Return type: anyarray

  • date_bpchar

    Description: Converts the date type to bpchar.

    Parameter: date

    Return type: character

  • date_text

    Description: Converts date to text.

    Parameter: date

    Return type: text

  • date_varchar

    Description: Converts date to varchar.

    Parameter: date

    Return type: character varying

  • f4toi1

    Description: Forcibly converts float4 to uint8.

    Parameter: real

    Return type: tinyint

  • f8toi1

    Description: Forcibly converts float8 to uint8.

    Parameter: double precision

    Return type: tinyint

  • float4_bpchar

    Description: Converts float4 to bpchar.

    Parameter: real

    Return type: character

  • float4_text

    Description: Converts float4 to text.

    Parameter: real

    Return type: text

  • float4_varchar

    Description: Converts float4 to varchar.

    Parameter: real

    Return type: character varying

  • float8_bpchar

    Description: Converts float8 to bpchar.

    Parameter: double precision

    Return type: character

  • float8_interval

    Description: Converts float8 to interval.

    Parameter: double precision

    Return type: interval

  • float8_text

    Description: Converts float8 to text.

    Parameter: double precision

    Return type: text

  • float8_varchar

    Description: Converts float8 to varchar.

    Parameter: double precision

    Return type: character varying

  • i1tof4

    Description: Converts uint8 to float4.

    Parameter: tinyint

    Return type: real

  • i1tof8

    Description: Converts uint8 to float8.

    Parameter: tinyint

    Return type: double precision

  • i1toi2

    Description: Converts uint8 to int16.

    Parameter: tinyint

    Return type: smallint

  • i1toi4

    Description: Converts uint8 to int32.

    Parameter: tinyint

    Return type: integer

  • i1toi8

    Description: Converts uint8 to int64.

    Parameter: tinyint

    Return type: bigint

  • i2toi1

    Description: Converts int16 to uint8.

    Parameter: smallint

    Return type: tinyint

  • i4toi1

    Description: Converts int32 to uint8.

    Parameter: integer

    Return type: tinyint

  • i8toi1

    Description: Converts int64 to uint8.

    Parameter: bigint

    Return type: tinyint

  • int1_avg_accum

    Description: Adds the second parameter of the uint8 type to the first parameter. The first parameter is an array of the bigint type.

    Parameter: bigint[], tinyint

    Return type: bigint[]

  • int1_bool

    Description: Converts uint8 to Boolean.

    Parameter: tinyint

    Return type: Boolean

  • int1_bpchar

    Description: Converts uint8 to bpchar.

    Parameter: tinyint

    Return type: character

  • int1_mul_cash

    Description: Returns the product of a parameter of the int8 type and a parameter of the cash type. The return type is cash.

    Parameter: tinyint, money

    Return type: money

  • int1_numeric

    Description: Converts uint8 to numeric.

    Parameter: tinyint

    Return type: numeric

  • int1_nvarchar2

    Description: Converts uint8 to nvarchar2.

    Parameter: tinyint

    Return type: nvarchar2

  • int1_text

    Description: Converts uint8 to text.

    Parameter: tinyint

    Return type: text

  • int1_varchar

    Description: Converts uint8 to varchar.

    Parameter: tinyint

    Return type: character varying

  • int1in

    Description: Converts a string into an unsigned 1-byte integer.

    Parameter: cstring

    Return type: tinyint

  • int1out

    Description: Converts an unsigned 1-byte integer into a string.

    Return type: cstring

  • int1up

    Description: Converts an input integer to an unsigned 1-byte integer.

    Parameter: tinyint

    Return type: tinyint

  • int2_bool

    Description: Converts a two-byte signed integer to the Boolean type.

    Parameter: smallint

    Return type: Boolean

  • int2_bpchar

    Description: Converts a signed two-byte integer to the bpchar type.

    Parameter: smallint

    Return type: character

  • int2_text

    Description: Converts a signed two-byte integer to the text type.

    Parameter: smallint

    Return type: text

  • int2_varchar

    Description: Converts a signed two-byte integer to the varchar type.

    Parameter: smallint

    Return type: character varying

  • int4_bpchar

    Description: Converts a signed four-byte integer to bpchar.

    Parameter: integer

    Return type: character

  • int4_text

    Description: Converts a signed four-byte integer to the text type.

    Parameter: integer

    Return type: text

  • int4_varchar

    Description: Converts a signed four-byte integer into varchar.

    Parameter: integer

    Return type: character varying

  • int8_bool

    Description: Converts an eight-byte signed integer to the Boolean value.

    Parameter: bigint

    Return type: Boolean

  • int8_bpchar

    Description: Converts an 8-byte signed integer to bpchar.

    Parameter: bigint

    Return type: character

  • int8_text

    Description: Converts an eight-byte signed integer to the text type.

    Parameter: bigint

    Return type: text

  • int8_varchar

    Description: Converts an eight-byte signed integer to varchar.

    Parameter: bigint

    Return type: character varying

  • intervaltonum

    Description: Converts the internal dats type date to numeric.

    Parameter: interval

    Return type: numeric

  • numeric_bpchar

    Description: Converts numeric to bpchar.

    Parameter: numeric

    Return type: character

  • numeric_int1

    Description: Converts numeric to a signed one-byte integer.

    Parameter: numeric

    Return type: tinyint

  • numeric_text

    Description: Converts numeric to text.

    Parameter: numeric

    Return type: text

  • numeric_varchar

    Description: Converts numeric to varchar.

    Parameter: numeric

    Return type: character varying

  • nvarchar2in

    Description: Converts c string to varchar.

    Parameter: cstring, oid, integer

    Return type: nvarchar2

  • nvarchar2out

    Description: Converts text into a c string.

    Parameter: nvarchar2

    Return type: cstring

  • nvarchar2send

    Description: Converts varchar to binary.

    Parameter: nvarchar2

    Return type: bytea

  • oidvectorin_extend

    Description: Converts a string to oidvector.

    Parameter: cstring

    Return type: oidvector_extend

  • oidvectorout_extend

    Description: Converts oidvector to a string.

    Parameter: oidvector_extend

    Return type: cstring

  • oidvectorsend_extend

    Description: Converts oidvector to a string.

    Parameter: oidvector_extend

    Return type: bytea

  • reltime_text

    Description: Converts reltime to text.

    Parameter: reltime

    Return type: text

  • text_date

    Description: Converts the text type to the date type.

    Parameter: text

    Return type: date

  • text_float4

    Description: Converts text to float4.

    Parameter: text

    Return type: real

  • text_float8

    Description: Converts the text type to float8.

    Parameter: text

    Return type: double precision

  • text_int1

    Description: Converts the text type to int1.

    Parameter: text

    Return type: tinyint

  • text_int2

    Description: Converts the text type to the int2 type.

    Parameter: text

    Return type: smallint

  • text_int4

    Description: Converts the text type to int4.

    Parameter: text

    Return type: integer

  • text_int8

    Description: Converts the text type to the int8 type.

    Parameter: text

    Return type: bigint

  • text_numeric

    Description: Converts the text type to the numeric type.

    Parameter: text

    Return type: numeric

  • text_timestamp

    Description: Converts the text type to the timestamp type.

    Parameter: text

    Return type: timestamp without time zone

  • time_text

    Description: Converts the time type to the text type.

    Parameter: time without time zone

    Return type: text

  • timestamp_text

    Description: Converts the timestamp type to the text type.

    Parameter: timestamp without time zone

    Return type: text

  • timestamp_to_smalldatetime

    Description: Converts the timestamp type to the smalldatetime type.

    Parameter: timestamp without time zone

    Return type: smalldatetime

  • timestamp_varchar

    Description: Converts the timestamp type to varchar.

    Parameter: timestamp without time zone

    Return type: character varying

  • timestamptz_to_smalldatetime

    Description: Converts timestamptz to smalldatetime.

    Parameter: timestamp with time zone

    Return type: smalldatetime

  • timestampzone_text

    Description: Converts the timestampzone type to the text type.

    Parameter: timestamp with time zone

    Return type: text

  • timetz_text

    Description: Converts the timetz type to the text type.

    Parameter: time with time zone

    Return type: text

  • to_integer

    Description: Converts data to the integer type.

    Parameter: character varying

    Return type: integer

  • to_interval

    Description: Converts to the interval type.

    Parameter: character varying

    Return type: interval

  • to_numeric

    Description: Converts to the numeric type.

    Parameter: character varying

    Return type: numeric

  • to_text

    Description: Converts to the text type.

    Parameter: smallint

    Return type: text

  • to_ts

    Description: Converts to the ts type.

    Parameter: character varying

    Return type: timestamp without time zone

  • to_varchar2

    Description: Converts to the varchar2 type.

    Parameter: timestamp without time zone

    Return type: character varying

  • varchar_date

    Description: Converts varchar to date.

    Parameter: character varying

    Return type: date

  • varchar_float4

    Description: Converts varchar to float4.

    Parameter: character varying

    Return type: real

  • varchar_float8

    Description: Converts the varchar type to the float8 type.

    Parameter: character varying

    Return type: double precision

  • varchar_int4

    Description: Converts the type from varchar to int4.

    Parameter: character varying

    Return type: integer

  • varchar_int8

    Description: Converts the varchar type to the int8 type.

    Parameter: character varying

    Return type: bigint

  • varchar_numeric

    Description: Converts varchar to numeric.

    Parameter: character varying

    Return type: numeric

  • varchar_timestamp

    Description: Converts varchar to timestamp.

    Parameter: character varying

    Return type: timestamp without time zone

  • varchar2_to_smlldatetime

    Description: Converts varchar2 to smlldatetime.

    Parameter: character varying

    Return type: smalldatetime

  • xidout4

    Description: The xid output is a four-byte number.

    Parameter: xid32

    Return type: cstring

  • xidsend4

    Description: Converts xid to the binary format.

    Parameter: xid32

    Return type: bytea

  • treat(expr AS [JSON | REF] schema.type)

    Description: Converts expr to the type (JSON) specified by the keyword after AS.

    Return value type: JSON.

    Example:

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    gaussdb=# CREATE TABLE json_doc(data CLOB);
    gaussdb=# INSERT INTO json_doc VALUES('{"name":"a"}');
    gaussdb=# SELECT treat(data as json) FROM json_doc;
         json     
    --------------
     {"name":"a"}
    (1 row)
    gaussdb=# DROP TABLE json_doc;
    DROP TABLE
    

Encoding Type Conversion

  • convert_to_nocase(text, text)

    Description: Converts a string into a specified encoding type.

    Return type: bytea

    Example:

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    gaussdb=# SELECT convert_to_nocase('12345', 'GBK');
     convert_to_nocase 
    -------------------
     \x3132333435
    (1 row)