Hash indexes only support the equality operator, they're not as versatile as btree indexes (see https://www.postgresql.org/docs/devel/static/indexes-types.html

Hash indexes only support the equality operator, they're not as versatile as btree indexes (see https://www.postgresql.org/docs/devel/static/indexes-types.html https://www.postgresql.org/docs/devel/static/indexes-types.h...).