On Tue, 2024-11-19 at 14:30 +0100, Moreno Andreo wrote: > Inhttps://www.cybertec-postgresql.com/en/join-strategies-and-performance-in-postgresql/ > you say > "Note that for inner joins there is no distinction between the join > condition and the WHERE condition, but that doesn't hold for outer joins." > What do you mean?
CREATE TABLE a (id integer); INSERT INTO a VALUES (1), (2), (3); CREATE TABLE b (id integer); INSERT INTO b VALUES (1), (2), (4); SELECT * FROM a JOIN b ON a.id = b.id AND b.id < 2; id │ id ════╪════ 1 │ 1 (1 row) SELECT * FROM a JOIN b ON a.id = b.id WHERE b.id < 2; id │ id ════╪════ 1 │ 1 (1 row) SELECT * FROM a LEFT JOIN b ON a.id = b.id AND b.id < 2; id │ id ════╪════ 1 │ 1 2 │ ∅ 3 │ ∅ (3 rows) SELECT * FROM a LEFT JOIN b ON a.id = b.id WHERE b.id < 2; id │ id ════╪════ 1 │ 1 (1 row) Yours, Laurenz Albe
