Re: need some more select help

From: Greg Stark <stark(at)mit(dot)edu>
To: A B <gentosaker(at)gmail(dot)com>
Cc: "pgsql-novice(at)postgresql(dot)org" <pgsql-novice(at)postgresql(dot)org>
Subject: Re: need some more select help
Date: 2009-07-17 15:50:15
Message-ID: C4ADAEC1-FADC-48A8-B7A1-56FFE21578A5@mit.edu
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You just need "AS x" x after the subquery.

However I think you have other problems with these queries. UNION
eliminates duplicates so your group by will only ever give a count of 1.

You could use UNION ALL. or you might use two separate grouped
subqueries and the sum the two together.

--
Greg

On 2009-07-17, at 9:23 AM, A B <gentosaker(at)gmail(dot)com> wrote:

> I'm trying to
>
> select a,count(1) FROM (select a from X UNION select a from Y )
> group by a;
>
> but it complains and says that the subquery must have an alias and I
> have not figured it out how to add that.
>
> Btw. is there any other way of doing what I'm doing above?
>
> It's basically select a,count(1) from X group by a + select
> a,count(1) from Y group by a where "+" means they should be summed
> on the "a" field.
>
> I tried
> select a,sum(b) from ( select a,count(1) as b from X group by a
> union select a,count(1) as b from Y group by a) group by a
>
> but that gave also an error asking for an alias for the subquery.
>
> How can I solv this problem?
>
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