Re: Adding AVG to a JOIN
| От | David G. Johnston |
|---|---|
| Тема | Re: Adding AVG to a JOIN |
| Дата | |
| Msg-id | CAKFQuwZj0wqBVfKpJfuyhavzvX4CkHP4m-b9AfMKTWHkA9HpBw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Adding AVG to a JOIN (Alexander Farber <alexander.farber@gmail.com>) |
| Ответы |
Re: Adding AVG to a JOIN
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| Список | pgsql-general |
SELECTu.elo,AVG(c.played - c.prev_played) AS avg_time_per_move,(SELECT ROUND(AVG(score), 1) FROM words_moves WHERE uid = u.uid) AS score,And I don't understand why adding a CTE has caused it, because without the CTE the GROUP BY u.elo was not required...
Adding "AVG(c.played - c.prev_played)" directly to the top-level select statement column list is what turned it into a "GROUP BY" query. When you embedded the "AVG(score)" in a subquery the GROUP BY was limited to just that subquery, and it had no other columns besides the aggregate and so didn't require a GROUP BY clause.
David J.
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