Re: joining VIEWs

On Tue, 22 Aug 2006, Brian Cox wrote:

> Given a view like:
>
> create view view1 as
> select g.id as UserGroupId, s.uid as UserId, s.time as StartTime from stats s join groups g on g.uid = s.uid
>
> and a SELECT like:
>
> select a.UserGroupId,b.UserGroupId from view1 a
> full outer join view1 b on b.UserGroupId = a.UserGroupId
> WHERE a.StartTime >= '2006-1-1' AND a.StartTime < '2007-1-1'
> AND b.StartTime >= '2005-1-1' AND b.StartTime < '2006-1-1';
>
> where there are 5695 rows in 2006 and 1 row in 2005, I expected to get
> a result set of 5695 rows, but instead got only 1 row (the common row
> in the 2 years). This seems contrary to the definition of "full outer
> join". Am I missing something?

The where clause is applied after the join. If you want to filter the rows
before/during the join itself you can use subselects in the from clause or
put the additional conditions in the on condition.