What is the purpose of `LATERAL` join in PostgreSQL and what does it enable?

Question

Advanced SQL Developer — Medium

What is the purpose of `LATERAL` join in PostgreSQL and what does it enable?

Accepted Answer

The purpose of `LATERAL` join in PostgreSQL is to allow a subquery in the FROM clause to reference columns from preceding FROM items. This enables correlated subqueries in FROM position, TOP-N per group patterns, and functions returning sets that depend on outer table values.