You can't reference aliases in the field list or Where clauses.

You can in the Having and Order By though.

Tigger


Stan R. wrote:
> Take this query I'm running from the mysql commandline:
>
> SELECT name,
> SUM(joined_0) AS J0,
> SUM(joined_1) AS J1,
> ABS(SUM(joined_0) - SUM(joined_1)) AS J_Diff,
> SUM(joined_0)/(SUM(joined_0) + SUM(joined_1))*100 AS J0_Pcnt,
> SUM(joined_1)/(SUM(joined_0) + SUM(joined_1))*100 AS J1_Pcnt
> FROM ps_people p,
> ps_pdata d,
> ps_pdata_etc e
> WHERE d.dataid = e.dataid AND
> d.pid = p.pid
> GROUP BY d.plrid
> HAVING J0 > 0 AND
> J1 > 0
> ORDER BY J_Diff ASC
> LIMIT 20;
>
>
>
>
> 1) Why is it I can't use J0 and J1 in the definition for J_Diff and
> J0_Pcnt, J1_Pcnt
>
> 2) Is there any way to do it that I'm missing here?
>
> I guess mainly I want ot save typing and it seems really redundant and
> error prone to write a query the way I wrote it, and aliasing seemed
> like it would make things less cluttered but all I get is 'Unknown
> Column'
>
> Thanks for any help.