CAST Function [Data Type Conversion]

Returns the value of an expression converted to a supplied data type.

Syntax

CAST ( expression AS data type )

Parameters

Parameters	Description
expression	The expression to be converted.
data type	The target data type.

Returns

The specified data type.

Examples

The following function ensures a string is used as a date:

CAST( '2000-10-31' AS DATE )

The value of the expression 1 + 2 is calculated, and the result cast into a single-character string, the length the data server assigns:

CAST( 1 + 2 AS CHAR )

You can use the CAST function to shorten strings:

SELECT CAST( lname AS CHAR(5) ) FROM Customers

Usage

If you do not indicate a length for character string types, Sybase IQ chooses an appropriate length. If neither precision nor scale is specified for a DECIMAL conversion, the database server selects appropriate values.

If neither precision nor scale is specified for the explicit conversion of NULL to NUMERIC, the default is NUMERIC(1,0). For example,

SELECT CAST( NULL AS NUMERIC ) A,
       CAST( NULL AS NUMERIC(15,2) ) B

is described as:

A NUMERIC(1,0)
B NUMERIC(15,2)

Standards and Compatibility

SQL—ISO/ANSI SQL compliant.
Sybase—Compatible with Adaptive Server Enterprise.