Updated on 2025-08-19 GMT+08:00

Logical Operators

Common logical operators include AND, OR, and NOT. The operation result has three values: TRUE, FALSE, and NULL. NULL indicates unknown. Their priorities are NOT > AND > OR.

Table 1 lists the calculation rules, where a and b represent logical expressions.

**Table 1** Operation rules
a	b	a AND b Result	a OR b Result	NOT a Result
TRUE	TRUE	TRUE	TRUE	FALSE
TRUE	FALSE	FALSE	TRUE	FALSE
TRUE	NULL	NULL	TRUE	FALSE
FALSE	FALSE	FALSE	FALSE	TRUE
FALSE	NULL	FALSE	NULL	TRUE
NULL	NULL	NULL	NULL	NULL

The operators AND and OR are commutative, that is, you can switch the left and right operand without affecting the result.

Parent topic: Functions and Operators

Logical Operators

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