# Logical Operators

Logical terms let you combine other expressions using Boolean logic. N1QL provides the following logical operators:

• AND

• OR

• NOT

In N1QL, logical operators have their usual meaning. However, in any of these expressions, if any operand is MISSING, the value of the expression is MISSING. If any operand is NULL and no operand is MISSING, the value of the expression is NULL. See the description of the OR operator for an exception to this rule.

## AND

`condition AND condition`

AND evaluates to TRUE only if both conditions are TRUE.

Table 1. AND Truth Table
TRUE FALSE

TRUE

TRUE

FALSE

FALSE

FALSE

FALSE

## OR

`condition OR condition`

OR evaluates to TRUE if one of the conditions is TRUE.

Table 2. OR Truth Table
TRUE FALSE

TRUE

TRUE

TRUE

FALSE

TRUE

FALSE

 The OR operator has an exception to the general rule that operators return MISSING or NULL if their operands are MISSING or NULL. If one operand of the OR operator is TRUE and the other operand is MISSING or NULL, the OR operator returns TRUE.

## NOT

`NOT condition`

NOT evaluates to TRUE if the expression does not match the condition.

## Logical Truth Table

x y x AND y x OR y NOT x

TRUE

TRUE

TRUE

TRUE

FALSE

TRUE

FALSE

FALSE

TRUE

FALSE

TRUE

NULL

NULL

TRUE

FALSE

TRUE

MISSING

MISSING

TRUE

FALSE

**

**

FALSE

TRUE

FALSE

TRUE

TRUE

FALSE

FALSE

FALSE

FALSE

TRUE

FALSE

NULL

FALSE

NULL

TRUE

FALSE

MISSING

MISSING

MISSING

TRUE

**

**

NULL

TRUE

NULL

TRUE

NULL

NULL

FALSE

FALSE

NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

MISSING

MISSING

MISSING

NULL

**

**

MISSING

TRUE

MISSING

TRUE

MISSING

MISSING

FALSE

MISSING

MISSING

MISSING

MISSING

NULL

MISSING

MISSING

MISSING

MISSING

MISSING

MISSING

MISSING

MISSING