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Posted by Boris Stumm on 05/15/07 09:31
Tyno Gendo wrote:
> i'm just wondering, is it possible to count the number of rows without
> NULL/blanks in for two columns in one select?
>
> I tried: SELECT module.*, COUNT( modpr_prereq ) AS prereq_count, COUNT(
> mods_slide ) AS step_count FROM module LEFT JOIN mod_prereqs ON
> mod_prereqs.modpr_mod = module.mod_seq LEFT JOIN mod_slide ON
> mod_slide.mods_mod_seq = module.mod_seq GROUP BY mod_seq;
Instead of count(col) you can do a
sum(case when col is null then 0 else 1 end)
I am not sure if that is the most clever solution, and if it works with
MySQL, but for me it worked when I wanted two counts in one select.
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