having example.

hi can anyone explain to me the diff between having and where?
set1
a b
1 2
1 NULL
1 3
2 NULL
2 1
1 NULL
select a,b from set1
where b =2
group by a,b
and
select a,b from set1
group by a,b
having b =2
both the above querries give me teh same result.
so i cant tell teh difference.WHERE applies before the grouping and aggregation, HAVING applies
afterwards the aggregation.
HTH, Jens Suessmeyer.|||You can use HAVING to apply a filter on grouped sets like
select a,b from set1
group by a,b
having COUNT(8) >2
Otherwise HAVING servers the same purpose as WHERE
Regards
Roji. P. Thomas
http://toponewithties.blogspot.com
"ichor" <ichor@.hotmail.com> wrote in message
news:uiO5W9PPGHA.3528@.TK2MSFTNGP10.phx.gbl...
> hi can anyone explain to me the diff between having and where?
> set1
> a b
> 1 2
> 1 NULL
> 1 3
> 2 NULL
> 2 1
> 1 NULL
>
> select a,b from set1
> where b =2
> group by a,b
> and
> select a,b from set1
> group by a,b
> having b =2
>
> both the above querries give me teh same result.
> so i cant tell teh difference.
>