On 2023-11-15 10:57 +0100, Dimitrios Apostolou wrote: > SELECT [DISTINCT] ... EXCEPT ... > > In this query I get the same results regardless of including DISTINCT or > not. But I get different query plans, I get an extra HashAggregate node > in the case of SELECT DISTINCT. Any idea why?
As Tom Lane recently wrote[1] EXCEPT is not optimized and will operate on the subqueries which are planned independently. [1] https://www.postgresql.org/message-id/2664450.1698799...@sss.pgh.pa.us -- Erik
