Re: simple? join
От | Christopher Kings-Lynne |
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Тема | Re: simple? join |
Дата | |
Msg-id | GNELIHDDFBOCMGBFGEFOCEAMCBAA.chriskl@familyhealth.com.au обсуждение исходный текст |
Ответ на | Re: simple? join (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: simple? join
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Список | pgsql-sql |
> So, when and if we get around to implementing this particular SQL99 > feature, what you are suggesting will work. Right now it doesn't > (and I'll wager that darn few other SQL implementations support this > feature as yet, either). I think MySQL does. I always found it strange that I had to add columns to the group by clause in postgres that were functionally dependent on the "real" grouped variable. In fact, before I realised that you had to add them to the group by clause, I just wrapped the functionally dependent fields in a MAX function (or min, whatever). ie. SELECT orders.product_id, MAX(product_name), MAX(unit_price) FROM products NATURAL JOIN orders GROUP BY orders.product_id; In fact, if one created a 'do nothing' aggregate function, you could avoid having to add things to the group by clause in a cleaner fashion. Chris
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