til/postgres/set-inclusion-with-hstore.md

Set Inclusion With hstore

In PostgreSQL, hstore records can be compared via set inclusion. The @> and <@ operators can be used for this. The @> operator checks if the right operand is a subset of the left operand. The <@ operator checks if the left operand is a subset of the right operand.

> select '"one"=>"1", "two"=>"2", "three"=>"3"'::hstore @> '"two"=>"2"'::hstore;
 ?column?
 ----------
  t

> select '"one"=>"1", "two"=>"2", "three"=>"3"'::hstore <@ '"two"=>"2"'::hstore;
 ?column?
----------
 f

See the hstore PostgreSQL docs for more details.