Question

I’ve to fill an empty table (TAB_A) with random records (5%) from TAB_B, joined with other 3 tables (C1, C2, C3).

Now, if I run the following query everything works well:

INSERT INTO TAB_A (field1,field2)
    SELECT TAB_B.ID_TASS, TAB_B.ID_SEZ
    FROM (SELECT TAB_B.*, row_number() 
            OVER (ORDER BY dbms_random.VALUE) r 
            FROM TAB_B) 
    WHERE r < (SELECT COUNT(*) FROM TAB_B)*0.05

The problem is that I need also to fill in the TAB_A.field3 whose values are in TAB_C3.
So I rewrite my previous query:

INSERT INTO TAB_A (field1,field2,field3)
    SELECT B.ID_TASS, B.ID_SEZ, C3.Z_ID
    FROM (SELECT B.*, row_number() 
            OVER (ORDER BY dbms_random.VALUE) r 
            FROM TAB_B B
                JOIN TAB_C1 C1 on C1.X_ID = B.X_ID
                JOIN TAB_C2 C2 on C2.Y_ID = C1.Y_ID
                JOIN TAB_C3 C3 on C3.Z_ID = C2.Z_ID
            WHERE C3.Z_ID = 9) 
    WHERE r < (SELECT COUNT(*) FROM B)*0.05

but an error occurs: ORA-00904: “C3.Z_ID” invalid identifier.

I think the problem could be in the statement “SELECT B.ID_TASS, B.ID_SEZ, C3.Z_ID“, that I changed in “SELECT TAB_B.ID_TASS, TAB_B.ID_SEZ, TAB_C3.Z_ID“…. but without success: the same error occurs again.

By the way, the following query works perfectely:

select count(*)
    from TAB_B B
        JOIN TAB_C1 C1 on C1.X_ID = B.X_ID
        JOIN TAB_C2 C2 on C2.Y_ID = C1.Y_ID
        JOIN TAB_C3 C3 on C3.Z_ID = C2.Z_ID
    WHERE C3.Z_ID = 9

Can anybody help me?

Answer 1

try

…

SELECT B.ID_TASS, B.ID_SEZ, C3_Z_ID

FROM (SELECT B.*, C3.Z_ID AS C3_Z_ID, row_number()
…