What is the difference between LATERAL and a subquery in PostgreSQL?

Question

Since Postgres came out with the ability to do LATERAL joins, I\'ve been reading up on it, since I currently do complex data dumps for my team with lots of inef

Answer 1

One thing no one has pointed out is that you can use LATERAL queries to apply a user-defined function on every selected row.

For instance:

CREATE OR REPLACE FUNCTION delete_company(companyId varchar(255))
RETURNS void AS $$
    BEGIN
        DELETE FROM company_settings WHERE "company_id"=company_id;
        DELETE FROM users WHERE "company_id"=companyId;
        DELETE FROM companies WHERE id=companyId;
    END; 
$$ LANGUAGE plpgsql;

SELECT * FROM (
    SELECT id, name, created_at FROM companies WHERE created_at < '2018-01-01'
) c, LATERAL delete_company(c.id);

That's the only way I know how to do this sort of thing in PostgreSQL.