Timeline for How to give precedence to rows from one table over matching rows in another?

10 events

when toggle format	what		by	license	comment
Nov 13, 2021 at 7:13	comment	added	user2616355		@ypercubeᵀᴹ would it be possible to have a full query or dbfiddle, I was trying and could not figure out how to do it.
Jun 5, 2021 at 23:07	comment	added	ypercubeᵀᴹ		@user2616355 yes, you could have a `CASE` expression in the SELECT list or a simple check, eg: `SELECT ..., (b.value IS NOT NULL) AS value_comes_from_b ...`
Jun 3, 2021 at 22:02	comment	added	user2616355		is it possible to know which table `COALESCE` matched in ?
Dec 21, 2017 at 4:00	comment	added	jpmc26		If you only need 1 row, won't the `JOIN` be just as efficient as the subqueries? In which case, I'd favor the improved readability and flexibility of the `JOIN`.
Dec 20, 2017 at 20:32	history	edited	ypercubeᵀᴹ	CC BY-SA 3.0	added 174 characters in body
Dec 20, 2017 at 20:25	history	edited	ypercubeᵀᴹ	CC BY-SA 3.0	added 174 characters in body
Dec 20, 2017 at 20:24	vote	accept	Code Poet
Dec 20, 2017 at 20:22	comment	added	ypercubeᵀᴹ		It's just a way to pass the parameter once (so it isn't in the two WHERE clauses). You could also expand the list of keys inside the VALUES, to more than one.
Dec 20, 2017 at 20:21	comment	added	Code Poet		`COALESCE` is brilliant. However, I don't understand what `(VALUES ('key.A')) AS prm (key)` is doing?
Dec 20, 2017 at 19:54	history	answered	ypercubeᵀᴹ	CC BY-SA 3.0