CAST

Purpose

You can call this function to convert one built-in data type to another built-in data type.

Syntax

CAST (expr AS type_name )

Parameters

Return type

This function returns the same data type as what you specified for the type_name parameter.

The following table describes the conversion relationships among the built-in data types.

Note

DATETIME/INTERVAL data types include DATE, TIMESTAMP, TIMESTAMP WITH TIMEZONE, INTERVAL DAY TO SECOND, and INTERVAL YEAR TO MONTH.

Examples

The following example converts the character string 123 to an integer, the integer 1 to the VARCHAR2(10) data type, and 22-OCT-2021 to the TIMESTAMP WITH LOCAL TIME ZONE data type.

obclient> SELECT CAST('123' AS INT),CAST(1 AS VARCHAR2(10)),CAST('22-OCT-2021' AS TIMESTAMP WITH LOCAL TIME ZONE)
    AS RESULT FROM DUAL;
+------------------+-----------------------+------------------------------+
 CAST('123'ASINT)  CAST(1ASVARCHAR2(10))  RESULT                       
+------------------+-----------------------+------------------------------+
              123  1                      22-OCT-21 12.00.00.000000 AM 
+------------------+-----------------------+------------------------------+
1 row in set

Note

This function is affected by the NLS_DATE_FORMAT parameter when you use it to convert a value of the DATE data type. You can execute the following statement to convert the NLS_DATE_FORMAT format first: ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';.