CAST

Allows you to convert data of one type to another type. CAST can be used wherever a constant can be used. CAST is useful in specifying the exact data type for an argument. This is especially true for unary operators like '-' or functions with one operand like TO_CHAR or TO_DATE.

A value can only be CAST to a compatible data type, with the exception of NULL. NULL can be cast to any other data type. CAST is not needed to convert a NULL to the desired target type in an insert select.

The following conversions are supported:

• Numeric value to numeric or BCD (Binary Coded Decimal)

• NCHAR to NCHAR

• CHAR string to BINARY string or DATE, TIME or TIMESTAMP

• BINARY string to BINARY or CHAR string

• DATE, TIME or TIMESTAMP to CHAR

SQL syntax

CAST
  ( {Expression | NULL} AS DataType )

Parameters

CAST has the parameters:

Description

• CAST to a domain name is not supported.

• Casting a selected value may cause the SELECT statement to take more time and memory than a SELECT statement without a CAST expression.

Examples

INSERT INTO t1 VALUES(TO_CHAR(CAST(? AS REAL)));
SELECT CONCAT(x1, CAST (? AS CHAR(10))) FROM t1;        
SELECT * FROM t1 WHERE CAST (? AS INT)=CAST(? AS INT);