Referencing an aliased subquery in Oracle

Question

I have the following query :

select
        A.A_ID,
        B.Lib,
        A.Lib,
        C.Lib,
        (SELECT count(*) FROM X WHERE A.A_ID = X.A_ID) AS countX,
        (SELECT count(*) FROM Y WHERE A.A_ID = Y.A_ID) AS countY,
        (SELECT count(*) FROM Z WHERE A.A_ID = Z.A_ID) AS countZ
    from
        A
    left outer join
        C
            on A.C_ID=C.C_ID
    left outer join
        B
            on A.B_ID=B.B_ID
    WHERE
        countX = 2 AND countY = 3
    ORDER BY 
        countZ DESC;

But this gives me the following error:

SQL Error [904] [42000]: ORA-00904: "COL_5_0_" : identificateur non valide

How can I solve this ?

Answer 1

try like below, i think you missed type group by it would be order by

with cte as
(

select
        A.A_ID,
        B.Lib,
        A.Lib,
        C.Lib,
        (SELECT count(*) FROM X WHERE A.A_ID = X.A_ID) AS countX,
        (SELECT count(*) FROM Y WHERE A.A_ID = Y.A_ID) AS countY,
        (SELECT count(*) FROM Z WHERE A.A_ID = Z.A_ID) AS countZ
    from
        A
    left outer join
        C
            on A.C_ID=C.C_ID
    left outer join
        B
            on A.B_ID=B.B_ID
) select * from cte where countX = 2 AND countY = 3
    Order BY 
    countZ DESC