Logical Operators in MySQL: AND, OR, and NOT
Logical operators in MySQL are used to combine or modify conditions in WHERE, HAVING, and JOIN clauses. They return TRUE (1), FALSE (0), or NULL depending on the evaluation.
Returns TRUE only if both conditions are TRUE.
If any condition is FALSE → result is FALSE.
If both are TRUE → TRUE.
If one is NULL and the other TRUE → result is NULL.
Used to filter rows that must satisfy multiple conditions.
Returns TRUE if at least one condition is TRUE.
Returns FALSE only if both conditions are FALSE.
If one is TRUE and other is NULL → TRUE.
Used to match either of multiple possible conditions.
Reverses the logical value of a condition.
NOT TRUE → FALSE.
NOT FALSE → TRUE.
NOT NULL → NULL (remains unknown).
AND: TRUE only when both are TRUE.
OR: TRUE if at least one is TRUE.
NOT: reverses TRUE/FALSE.
In summary: AND requires all conditions to be true, OR requires at least one, and NOT is used to negate a condition.