IN

IN is used to test if an expression is contained in a list of values.

This is also known as set membership.

Syntax

expr [ NOT ] IN  ( value_expr [, ...] )

Arguments

Parameter Description
expr A general value expression or a literal to test.
value_expr [, ...] A comma separated list of literal values of the same data type as expr

Returns

Returns TRUE when expr is contained in the set, or FALSE otherwise.

Notes

  • NULL is never equal to NULL, so to check if a value is NULL use IS NULL instead.
  • Using IN with more than 100 literal values can slow down query compilation. If your query relies on more than 100 values, consider using a lookup table and an inner join.

Examples

IN

farm=> SELECT name, num_eyes FROM cool_animals WHERE num_eyes IN (8, 10)
name           | num_eyes
---------------+---------
Spider         |        8
Horseshoe crab |       10

NOT IN

farm=> SELECT name, num_eyes FROM cool_animals WHERE num_eyes NOT IN (8, 10)
name           | num_eyes
---------------+---------
Box Jellyfish  |       24
Human          |        2
Fox            |        2
Possum         |        2