A Complex Non-Related Multi Table Query

  • Hi

     

    Tbl_A

    ColA

     

    Tbl_B

    ColB

     

    Tbl_C

    ColA

    ColB

    Tables don’t have any relation.

     

    In above table for my circumstances Tbl_C must have all combinations of Tbl_A.COlA & Tbl_B.Col.B (i.e. Tbl_C = Cartesian Product of Tbl_A & Tbl_B)

     

    But I got some rows missing.

    Can some one advise a query through which I can find combination of (Tbl_A.ColA & Tbl2_ColB) missing in Tbl_C

     

    Wishes

    Jawad

  • I have only a few minutes so I can't test it, but something along these lines should work. You create the "full" rowset (without missing records) using cross join, use it as a derived table, and then the LEFT JOIN should display rows that are missing in your Tbl_C. If that does not work, let us know - I hope I'll have more time later to look at it.

    SELECT * FROM

    (SELECT * FROM Tbl_A

    CROSS JOIN Tbl_B) as X

    LEFT JOIN Tbl_C C ON X.ColA = C.ColA AND X.ColB = C.ColB

    WHERE C.ColA IS NULL OR C.ColB IS NULL

    HTH, Vladan

    /edit: Did some tests now and it works for me. I suppose that you don't need to check for 'partial' rows in Tbl_C - I mean rows that have e.g. ColA=1 and ColB NULL - and you simply want to see which rows are missing. If yes, this should return what you need./

  • thanks

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