Join efficiency
От | Russ Brown |
---|---|
Тема | Join efficiency |
Дата | |
Msg-id | opsdncpjgfg2z5qo@relay.plus.net обсуждение исходный текст |
Ответы |
Re: Join efficiency
Re: Join efficiency Re: Join efficiency Re: Join efficiency Re: Join efficiency |
Список | pgsql-general |
Hello all, Recently a post on this list made me think a bit about the way in which I write my queries. I have always written queries with ordinary joins in this manner: SELECT * FROM a, b WHERE a.x=b.x; However I recently saw an laternative syntax: SELECT * FROM a JOIN b ON a.x=b.x; Is there any difference between these queries in terms of the speed of planning or the quality of the plan untimately used? I'd imagine that the second form provides more information that the planner may be able to use to make a better plan (or make a good plan more easily), but I've never had any problems with the first form. It also seems to me that the second form is more self-documenting, which is something I'm always in favour of. I'd appreciate anyone's thought/insight. Thanks. -- Russell Brown
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