Boolean predicate
Boolean values (
BOOLEAN) are compared in a Boolean predicate.Syntax
<bool predicate> ::= <column spec> [ IS [NOT] <TRUE | FALSE>]
column specExplanation
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 |