Hi Helio,
I understand the fact that "the inner query is executed before the outer query and the inner query doesn't even know about the outer query." But why the following query can be executed, although the inner query is using the outer query. Aren't we here using the same concept ? SELECT e1.empno,e1.ename,e1.job,e1.deptno, (select count(e2.empno) from emp e2 where e2.deptno = e1.deptno) as "Total" from emp e1; empno | ename | job | deptno | Total -------+--------+-----------+--------+------- 7839 | KING | PRESIDENT | 10 | 3 7698 | BLAKE | MANAGER | 30 | 6 7782 | CLARK | MANAGER | 10 | 3 7566 | JONES | MANAGER | 20 | 5 _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Helio Campos Mello de Andrade Sent: Thursday, October 30, 2008 2:53 PM To: [EMAIL PROTECTED] Cc: pgsql-sql@postgresql.org Subject: Re: [SQL] Subqueries The "v" reference need to exist in the inner query. You can't use an "outer query reference" in the inner query. This happens because the inner query is executed before the outer query and the inner query doesn't even know about the outer query. May be this helps you get what you want. SELECT *, count(pl.id <http://p.id/> ) * 1.5 AS nb_heures FROM sip_vacations_v v LEFT JOIN ( mat_grp_v mg INNER JOIN planification_v pl ON pl.mat_grp_id = mg.id <http://mg.id/> INNER JOIN planification_ens_v pe ON pe.planification_id = pl.id <http://p.id/> WHERE mg.annee_univ = v.annee and mg.semestre = v.sem_civ GROUP BY pe.emp_id, mg.mat_id, mg.groupe ) p ON p.emp_id = v.emp_id AND p.mat_id = v.mat_id AND p.groupe = v.groupe; I not sure about the count(pl.id <http://pl.id/> ) * 1.5 is the same that you are looking for because it will depend of what you ate looking for. Regards On Thu, Oct 30, 2008 at 10:17 AM, Pascal Tufenkji <[EMAIL PROTECTED]> wrote: Hello, I don't understand the following error. Can anyone help me plz Thx Pascal select * from sip_vacations_v v left join ( select pe.emp_id,mg.mat_id,mg.groupe,count(p.id) * 1.5 as nb_heures from mat_grp_v mg inner join planification_v p on p.mat_grp_id = mg.id inner join planification_ens_v pe on pe.planification_id = p.id where mg.annee_univ = v.annee and mg.semestre = v.sem_civ group by pe.emp_id,mg.mat_id,mg.groupe ) p on p.emp_id = v.emp_id and p.mat_id = v.mat_id and p.groupe = v.groupe ERROR: invalid reference to FROM-clause entry for table "v" LINE 9: where mg.annee_univ = v.annee and mg.semestre = v.sem_civ ^ HINT: There is an entry for table "v", but it cannot be referenced from this part of the query. -- Helio Campos Mello de Andrade