String Functions

String Operators

Table 1 lists common operation rules for string operators. A and B indicate string expressions.

Table 1 String operators

Operator

Returned Data Type

Description

A || B

STRING

Returns the string concatenated from A and B.

CHAR_LENGTH(A)

INT

Returns the number of characters in string A.

CHARACTER_LENGTH(A)

INT

Returns the number of characters in string A.

UPPER(A)

STRING

Returns the uppercase letter A.

LOWER(A)

STRING

Returns the lowercase letter a.

POSITION(A IN B)

INT

Returns the position where A first appears in B.

TRIM( { BOTH | LEADING | TRAILING } A FROM B)

STRING

Removes A at the start position, or end position, or both the start and end positions from B. By default, string expressions A at both the start and end positions are removed.

OVERLAY(A PLACING B FROM integer [ FOR B ])

STRING

Replaces A with B.

SUBSTRING(A FROM integer)

STRING

Returns the substring that starts from a fixed position of A. The start position starts from 1.

SUBSTRING(A FROM integer FOR integer)

STRING

Returns the substring starting from a fixed position and with the given length A. The start position starts from 1.

INITCAP(A)

STRING

Returns the string whose first letter is in uppercase and the other letters in lowercase. Words are sequences of alphanumeric characters separated by non-alphanumeric characters.

MD5(String expr)

STRING

Returns the md5 value of a string.

SHA1(String expr)

STRING

Returns the SHA1 value of a string.

SHA256(String expr)

STRING

Returns the SHA256 value of a string.

replace(String expr, String toreplace, String replace)

STRING

Replaces all "toreplace" in the expr string with "replace".

hash_code(String expr)

INT

Obtains the hash value. In addition to string, the parameter supports int, bigint, float, and double.

string_to_array(value, delimiter)

Array[String]

Separates the "value" string as character string arrays by using the delimiter.

CONCAT(String A, String B, ...)

STRING

Returns the concatenation result of two or more strings.

CONCAT_WS(String separator, String A, String B, ....)

STRING

Returns the concatenation result of two or more strings and uses separator as the delimiter to connect each string.

RPAD(String str, INT len, String pad)

STRING

Concatenates the pad string to the right of the str string until the length of the new string reaches the specified length len.

  • If the value of len is a negative number, value null is returned.
  • If the value of len is less than the length of str, the string obtained from cutting the str string to the length of len is returned.

LPAD(String str, INT len, String pad)

STRING

Concatenates the pad string to the left of the str string until the length of the new string reaches the specified length len.

  • If the value of len is a negative number, value null is returned.
  • If the value of len is less than the length of str, the string obtained from cutting the str string to the length of len is returned.