Syntax

Description of the illustration to_boolean.eps

Purpose

Use TO_BOOLEAN to explicitly convert character value expressions or numeric value expressions to boolean values.

If expr is a string, it must evaluate to the allowed string inputs. See Table 2-6.

expr can take one of the following types, or null:

• A character string of type CHAR, VARCHAR2, NCHAR, NVARCHAR2

• A numeric value of type NUMBER, BINARY_FLOAT, or BINARY_DOUBLE

• A boolean value of type BOOLEAN.

Examples

SELECT TO_BOOLEAN(0), TO_BOOLEAN('true'), TO_BOOLEAN('no');

The output is:

TO_BOOLEAN( TO_BOOLEAN( TO_BOOLEAN(
----------- ----------- -----------
FALSE       TRUE        FALSE

SELECT TO_BOOLEAN(1) FROM DUAL;

The output is:

TO_BOOLEAN( 
----------- 
TRUE