Horton

Re: Query help

David G. Johnston <david.g.johnston@gmail.com>

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From: "David G. Johnston" <david.g.johnston@gmail.com>
To: Adrian Klaver <adrian.klaver@aklaver.com>
Cc: John W Higgins <wishdev@gmail.com>, pgsql-general <pgsql-general@postgresql.org>
Date: 2019-01-01T20:05:41Z
Lists: pgsql-general 
On Tuesday, January 1, 2019, Adrian Klaver <adrian.klaver@aklaver.com>
wrote:

> On 1/1/19 11:26 AM, John W Higgins wrote:
>>
>> with accounts_over_total as (
>> select accountid from transactions where sum(amount) >= 50 group by
>> accountid)
>>
>
> Unfortunately there is a hitch in the above:(
>
> select p_item_no from projection where sum(qty) > 100 group by(p_item_no);
> ERROR:  aggregate functions are not allowed in WHERE
>

Which is where the HAVING clause comes in.  It filters out groups based on
an expression containing an aggregate function.

David J.