This documentation is for an unsupported version of PostgreSQL.
You may want to view the same page for the
current
version, or one of the other supported versions listed above instead.
The usual logical operators are available:
SQL uses a three-valued logic
system with true, false, and
null, which
represents
"unknown". Observe the
following truth tables:
The operators AND and OR are commutative, that is, you can switch the left
and right operand without affecting the result. But see Section 4.2.14 for
more information about the order of evaluation of
subexpressions.