SQL逻辑运算符

NuoDB supports the following logical operators: AND, OR, NOT.

NuoDB uses a three-valued logic system with true, false, and null, which represents unknown. See the following tables.

a b A和B. A或B.

TRUE

TRUE

TRUE

TRUE

TRUE

FALSE

FALSE

TRUE

TRUE

NULL

NULL

TRUE

FALSE

FALSE

FALSE

FALSE

FALSE

NULL

FALSE

NULL

NULL

NULL

NULL

NULL

a 不是A.

TRUE

FALSE

FALSE

TRUE

NULL

NULL

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