Help Center/ GaussDB(DWS)/ More Documents/ Tool Guide (Kuala Lumpur Region)/ DSC: SQL Syntax Migration Tool/ Teradata Syntax Migration/ Type Casting and Formatting
Updated on 2023-03-17 GMT+08:00
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Type Casting and Formatting

This section describes the syntax for migrating Teradata type casting and formatting. The migration syntax determines how the keywords and features are migrated.

In Teradata, the FORMAT keyword is used for formatting a column/expression. FORMAT '9(n)' and 'z(n)' are addressed using LPAD with 0 and space (' ') respectively. Data typing can be done using CAST or direct data type [like (expression1)(CHAR(n))]. This feature is addressed using CAST.

The following type casting and formatting statements are supported by the DSC:

CHAR

Input - Data type casting for CHAR

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(expression1)(CHAR(n))

Output

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CAST( (expression1) AS CHAR(n) )

COLUMNS and COLUMN ALIAS

Input - Type casting and formatting of a column should ensure the column name is the same as the column alias

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SELECT Product_Line_ID, MAX(Standard_Price) 
  FROM ( SELECT A.Product_Description, A.Product_Line_ID
   , A.Standard_Price(DECIMAL(18),FORMAT '9(18)')(CHAR(18))  
        FROM product_t A
      WHERE Product_Line_ID in (1, 2) 
  ) AS tabAls 
 GROUP BY Product_Line_ID;

Output

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SELECT Product_Line_ID, MAX( Standard_Price )
   FROM  ( SELECT A.Product_Description, A.Product_Line_ID
        , CAST( LPAD( CAST(A.Standard_Price AS DECIMAL( 18 ,0 )), 18, '0' ) AS CHAR( 18 ) ) AS Standard_Price 
                 FROM product_t A
               WHERE Product_Line_ID IN( 1 ,2 )
           ) AS tabAls
  GROUP BY Product_Line_ID;

Expressions

Input - Type casting and formatting of an expression

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SELECT product_id, standard_price*100.00(DECIMAL (17),FORMAT '9(17)' )(CHAR(17) ) AS order_amt 
   FROM db_pvfc9_std.Product_t 
  WHERE product_line_id is not null ;

Output

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SELECT product_id, CAST(LPAD(CAST(standard_price*100.00 AS DECIMAL(17)), 17, '0') AS CHAR(17)) AS order_amt 
   FROM db_pvfc9_std.Product_t 
   WHERE product_line_id is not null ;

INT

Input - Data type casting for INT

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SELECT
          CAST( col1 AS INT ) (
               FORMAT '9(5)'
          )
     FROM
          table1
;

Output

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SELECT
          LPAD( CAST( col1 AS INT ) ,5 ,'0' )
     FROM
          table1
;

Input - Data type casting for INT

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SELECT
          CAST( col1 AS INT ) (
               FORMAT '999999'
          )
     FROM
          table1
;

Output

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SELECT
          LPAD( CAST( col1 AS INT ) ,6 ,'0' )
     FROM
          table1
;

Input - Data type casting for INT

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SELECT
          CAST( expression1 AS INT FORMAT '9(10)' )
     FROM
          table1
;

Output

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SELECT
          LPAD( CAST( expression1 AS INT ) ,10 ,'0' )
     FROM
          table1
;

Input - Data type casting for INT

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SELECT
          CAST( expression1 AS INT FORMAT '9999' )
     FROM
          table1
;

Output

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SELECT
          LPAD( CAST( expression1 AS INT ) ,4 ,'0' )
     FROM
          table1
;

DATE

In Teradata, when casting DATE from one format to another format, AS FORMAT is used. Migration tools will add TO_CHAR function to retain the specified input format.

For details, see Date and Time Functions.

Input - Data type casting without DATE keyword

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SELECT
      CAST( CAST( '2013-02-12' AS DATE FORMAT 'YYYY/MM/DD' ) AS FORMAT 'DD/MM/YY' )
;

Output

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SELECT
      TO_CHAR( CAST( '2013-02-12' AS DATE ) ,'DD/MM/YY' )
;

DAY to SECOND

Input - Data type casting DAY to SECOND

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SELECT CAST(T1.Draw_Gold_Dt || ' ' ||T1.Draw_Gold_Tm as Timestamp)
- CAST(T1.Tx_Dt || ' '|| T1.Tx_Tm as Timestamp)  DAY(4) To SECOND  from db_pvfc9_std.draw_tab T1;

Output

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SELECT
          CAST(( CAST( T1.Draw_Gold_Dt || ' ' || T1.Draw_Gold_Tm AS TIMESTAMP ) - CAST(T1.Tx_Dt || ' ' || T1.Tx_Tm AS TIMESTAMP ) ) AS INTERVAL DAY ( 4 ) TO SECOND )
     FROM
          db_pvfc9_std.draw_tab T1
;

DECIMAL

Input - Data type casting for DECIMAL

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SELECT
          standard_price (
               DECIMAL( 17 )
               ,FORMAT '9(17)'
          ) (
               CHAR( 17 )
          )
     FROM
          db_pvfc9_std.Product_t
;

Output

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SELECT
          CAST( LPAD( CAST( standard_price AS DECIMAL( 17 ,0 ) ) ,17 ,'0' ) AS CHAR( 17 ) )
     FROM
          db_pvfc9_std.Product_t
;

Input - Data type casting for DECIMAL

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SELECT
          standard_price (
               DECIMAL( 17 ,0 )
               ,FORMAT '9(17)'
          ) (
               VARCHAR( 17 )
          )
     FROM
          db_pvfc9_std.Product_t
;

Output

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SELECT
          CAST( LPAD( CAST( standard_price AS DECIMAL( 17 ,0 ) ) ,17 ,'0' ) AS VARCHAR( 17 ) )
     FROM
          db_pvfc9_std.Product_t
;

Input - Data type casting for DECIMAL

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SELECT
          customer_id (
               DECIMAL( 17 )
          ) (
               FORMAT '9(17)'
          ) (
               VARCHAR( 17 )
          )
     FROM
          db_pvfc9_std.Customer_t
;

Output

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SELECT
          CAST( LPAD( CAST( customer_id AS DECIMAL( 17 ,0 ) ) ,17 ,'0' ) AS VARCHAR( 17 ) )
     FROM
          db_pvfc9_std.Customer_t
;

Time Interval

Type casting to time intervals is supported in DDL and DML. It is supported within SELECT and can be used in subqueries of VIEW, MERGE, and INSERT.

Input - Data type casting to time intervals

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SELECT TIME '06:00:00.00' HOUR TO SECOND;

Output

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SELECT TIME '06:00:00.00';

Input - Data type casting to time intervals with TOP

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SELECT TOP 3 * FROM dwQErrDtl_mc.C03_CORP_AGENT_INSURE 
WHERE Data_Dt > (SELECT TIME '06:00:00.00' HOUR TO SECOND);

Output

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SELECT  * FROM dwQErrDtl_mc.C03_CORP_AGENT_INSURE WHERE  Data_Dt > (SELECT TIME '06:00:00.00')   limit 3;

NULL

DSC will migrate an expression in the form NULL(data_type) to CAST(NULL AS replacement_data_type).

Input - Data type casting for NULL

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NULL(VARCHAR(n))

Output

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CAST(NULL AS VARCHAR(n))

Implicit Type Casting Issues

Input - Implicit TYPE CASTING ISSUES

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SELECT Data_Type,Start_Dt,End_Dt
 FROM (
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT '101' AS Data_Type,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')-1 AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
  ) TT
  UNION ALL
  SELECT '201' AS Data_Type,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')-7 AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
  FROM Sys_Calendar.CALENDAR
  WHERE calendar_date = CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')
  AND Day_Of_Week = 1
  UNION ALL
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT '401' AS Data_Type,CAST('${TX_PRIMONTH_END}' AS DATE FORMAT 'YYYYMMDD') AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
   ) TT
  WHERE CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')=CAST('${TX_MONTH_END}' AS DATE FORMAT 'YYYYMMDD')
  UNION ALL
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT '501' AS Data_Type,CAST('${TX_PRIQUARTER_END}' AS DATE FORMAT 'YYYYMMDD') AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
   ) TT
  WHERE CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')=CAST('${TX_QUARTER_END}' AS DATE FORMAT 'YYYYMMDD')
  UNION ALL
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT '701' AS Data_Type,CAST('${TX_PRIYEAR_END}' AS DATE FORMAT 'YYYYMMDD') AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
   ) TT
  WHERE CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')=CAST('${TX_YEAR_END}' AS DATE FORMAT 'YYYYMMDD')
 ) T1
 ;

Output

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SELECT Data_Type,Start_Dt,End_Dt
 FROM (
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT CAST('101' AS TEXT) AS Data_Type,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')-1 AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
  ) TT
  UNION ALL
  SELECT CAST('201' AS TEXT) AS Data_Type,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')-7 AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
  FROM Sys_Calendar.CALENDAR
  WHERE calendar_date = CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')
  AND Day_Of_Week = 1
  UNION ALL
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT CAST('401' AS TEXT) AS Data_Type,CAST('${TX_PRIMONTH_END}' AS DATE FORMAT 'YYYYMMDD') AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
   ) TT
  WHERE CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')=CAST('${TX_MONTH_END}' AS DATE FORMAT 'YYYYMMDD')
  UNION ALL
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT CAST('501' AS TEXT) AS Data_Type,CAST('${TX_PRIQUARTER_END}' AS DATE FORMAT 'YYYYMMDD') AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
   ) TT
  WHERE CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')=CAST('${TX_QUARTER_END}' AS DATE FORMAT 'YYYYMMDD')
  UNION ALL
  SELECT Data_Type,Start_Dt,End_Dt 
  FROM (
   SELECT CAST('701' AS TEXT) AS Data_Type,CAST('${TX_PRIYEAR_END}' AS DATE FORMAT 'YYYYMMDD') AS Start_Dt,CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD') AS End_Dt
   ) TT
  WHERE CAST('${TX_DATE}' AS DATE FORMAT 'YYYYMMDD')=CAST('${TX_YEAR_END}' AS DATE FORMAT 'YYYYMMDD')
 ) T1
 ;