Re: outer joins
От | tjk@tksoft.com |
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Тема | Re: outer joins |
Дата | |
Msg-id | 200104041422.HAA10925@smtp3.tksoft.com обсуждение исходный текст |
Ответ на | outer joins (Algirdas Šakmanas <asakmanas@grafton.lt>) |
Список | pgsql-sql |
Algirdas, This should do the trick: SELECT a.id,b.name FROM a,b WHERE a.id=b.id UNION SELECT id,null FROM a WHERE id NOT IN (SELECT id FROM b); Troy > > Hi all, > > I'm new to postgre, I've changed my work and consequently now i'm moving > from MS plaform. > In MS SQL there are such constructs left or right outer join, in postgres > there are no such thing > > Can You offer me strategy to make query that selects from table (a) and > joins to it another (b) > on e.g. a.id=b.aid but joins so that in case there is no value in table b > NULL is left in result: > in MS SQL i've used query: > > select a.id, b.name from a left outer join b on a.id=b.aid > > table a table b > > id | aid | name > ----------- ---------------- > 1 1 | Tom > 2 3 | Sam > > result: > a.id | b.name > --------------------- > 1 | Tom > 2 | NULL > > thank you in advance > > Algirdas ©akmanas > IT manager > +370 99 90369 > asakmanas@grafton.lt > Grafton Entertainment > http://www.tvnet.lt > > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) >
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