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Boolean predicate (bool_predicate) 

Boolean values ( BOOLEAN) are compared in a boolean predicate.

Syntax

<bool_predicate> ::= <column_spec> [ IS [NOT] <TRUE | FALSE>]

column spec

Explanation

If only one column specification ( column_spec ) is specified, the syntax is identical to <column_spec> IS TRUE .

The column_spec must always denote a column with the data type BOOLEAN.

The following rules apply to the result of a boolean predicate:

Column value

IS TRUE

IS NOT TRUE

IS FALSE

IS NOT FALSE

false

false

true

true

false

undefined

undefined

undefined

undefined

undefined

true

true

false

false

true

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