Обсуждение: JOIN condition confusion

Hi,

I am wondering if there is a way to set conditions on a left joined
table without hosing the join altogether:

query = qq |SELECT p.*, a.user_id            FROM patient_dosing p            LEFT JOIN patient_assignment a
ONp.patient_id = a.patient_id            WHERE p.dose_type = 'Missed (AWOL)'            AND (p.dose_date >= $start_date
ANDp.dose_date <= $end_date)            -- the next two conditions hose the left join            -- AND a.end_date IS
NULL           -- AND lower(a.assign_type) = 'primary'            ORDER BY a.user_id, p.patient_id| if ($dbtype ne
"oracle");

Thanks much!
Tom

Thomas Good wrote:
> Hi,
> 
> I am wondering if there is a way to set conditions on a left joined
> table without hosing the join altogether:
> 
> query = qq |SELECT p.*, a.user_id
>              FROM patient_dosing p
>              LEFT JOIN patient_assignment a
>              ON p.patient_id = a.patient_id
>              WHERE p.dose_type = 'Missed (AWOL)'
>              AND (p.dose_date >= $start_date AND p.dose_date <= $end_date)
>              -- the next two conditions hose the left join
>              -- AND a.end_date IS NULL
>              -- AND lower(a.assign_type) = 'primary'
>              ORDER BY a.user_id, p.patient_id| if ($dbtype ne "oracle");

What do you want to happen? What do you mean by a left-join where the 
right-hand side has assign_type='primary'?

--   Richard Huxton  Archonet Ltd