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Help Reg. Query

  • July 27, 2009 at 10:53 am

    #137024

    There is a table A which has certain fields that point to the primary keys of different tables. While joining the tables, some of the columns for certain rows might contain null instead of a value.

    If there are 5 rows in table x, after joining the other tables, there should always be 5 rows.

    There is a table A and other tables B,C,D,E

    Assume the data in A is as follows:

    ColA ColB ColC ColD ColE

    1 2 3 4 5

    1 null 6 null null

    1 7 null 8 null

    1 null null null 9

    The colB corresponds to primary col of table B, colC to primary col of table C, cold to primary col of table D and cole to primary col of table E

    I need a query which would return the same 4 rows and the names instead of reference key values of the fields representing the primary key of the other tables.

  • July 27, 2009 at 11:12 am

    #1030659

    if you could provide the actual table definitions, you could get a more refined answer.

    basically what you want to do is LEFT join all the tables, so you get either a NULL description or the actual description if the key in TABLEA finds a match.

    SELECT

    TABLEA.*

    TABLEB.DESCRIP

    TABLEC.DESCRIP

    TABLED.DESCRIP

    TABLEE.DESCRIP

    FROM TABLEA

    LEFT OUTER JOIN TABLEB ON TABLEA.BID = TABLEB.BID

    LEFT OUTER JOIN TABLEC ON TABLEA.CID = TABLEB.CID

    LEFT OUTER JOIN TABLED ON TABLEA.DID = TABLEB.DID

    LEFT OUTER JOIN TABLEE ON TABLEA.EID = TABLEB.EID

    Lowell

    --help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!

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