Help Center/ GaussDB/ Developer Guide(Distributed_V2.0-8.x)/ SQL Reference/ Functions and Operators/ Logical Operators
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.
| 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.
- Operations on XML data are not supported.
Parent topic: Functions and Operators
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