Hi. I read the thread. Probably this fiddle will be helpful for testing:
https://dbfiddle.uk/?rdbms=postgres_12&fiddle=abe845142a5099d921d3729043fb8491 I recently encountered a problem: Why Window-specific functions do not allow DISTINCT to be used within the function argument list? sum( DISTINCT order_cost ) OVER ( PARTITION BY invoice_id ORDER BY invoice_id, group_id RANGE unbound preceeding and unbound following ) behavior is quite deterministic: ORDER BY will create peers in partition DISTINCT will get only one peer I resolve my problem via two subqueries, but it seems this logic may be applied to window functions (did not check this for other functions thought) -- Best regards, Eugen Konkov