Join question
От | Edward W. Rouse |
---|---|
Тема | Join question |
Дата | |
Msg-id | 04b101c8fef6$b3c87d50$1b5977f0$@com обсуждение исходный текст |
Ответы |
Re: Join question
Re: Join question |
Список | pgsql-sql |
<div class="Section1"><p class="MsoNormal">I have 2 tables, both have a user column. I am currently using a left join fromtable a to table b because I need to show all users from table a even those not having an entry in table b. The problemis I also have to include items from table b with that have a null user. There are some other criteria as well thatare simple where clause filters. So as an example:<p class="MsoNormal"> <p class="MsoNormal">Table a:<p class="MsoNormal">Org|user<pclass="MsoNormal">A | emp1<p class="MsoNormal">B | emp1<p class="MsoNormal">B | emp2<pclass="MsoNormal">B | emp3<p class="MsoNormal">C | emp2<p class="MsoNormal"> <p class="MsoNormal">Table b:<pclass="MsoNormal">Org|user|color<p class="MsoNormal">A |emp1|red<p class="MsoNormal">A |emp1|blue<p class="MsoNormal">A |null|pink<p class="MsoNormal">A |null|orange<p class="MsoNormal">B |emp1|red<p class="MsoNormal">B |emp3|red<p class="MsoNormal">B |null|silver<p class="MsoNormal">C |emp2|avacado<p class="MsoNormal"> <pclass="MsoNormal">If I:<p class="MsoNormal"> <p class="MsoNormal">select org, user, count(total)<p class="MsoNormal">froma left join b<p class="MsoNormal">on (a.org = b.org and a.user = b.user)<p class="MsoNormal">wherea.org = ‘A’<p class="MsoNormal">group by a.org, a.user<p class="MsoNormal">order by a.org, a.user<pclass="MsoNormal"> <p class="MsoNormal">I get:<p class="MsoNormal"> <p class="MsoNormal">Org|user|count<p class="MsoNormal">A |emp1|2<p class="MsoNormal">A |emp2|0<p class="MsoNormal">A |emp3|0<p class="MsoNormal"> <p class="MsoNormal">Butwhat I need is:<p class="MsoNormal"> <p class="MsoNormal">A |emp1|2<p class="MsoNormal">A |emp2|0<pclass="MsoNormal">A |emp3|0<p class="MsoNormal">A |null|2<p class="MsoNormal"> <p class="MsoNormal">Thanks,<pclass="MsoNormal">Edward W. Rouse</div>
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