SQL Novice with stupid question...


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Thread: SQL Novice with stupid question...

  1. #1
    Join Date
    Nov 2010
    Posts
    2

    SQL Novice with stupid question...

    What is the difference between the two statements below?

    select
    a.field1
    b.field2
    c.field1
    a.field2
    from
    file1 a
    file2 b
    file3 c
    where
    a.field1 = b.field1
    and b.field2 = c.field1

    select
    a.field1
    b.field2
    c.field1
    a.field2
    from
    file1 a
    join file2 b on a.field1 = b.field1
    join file3 c on b.field2 = c.field1

  2. #2
    Join Date
    Oct 2010
    Posts
    22

    Dear Stupid

    Ok, I had to say it

    Your "from <- SELECTING" file1 a,file2 b,file3 c in first statement.

    Your "from <- SELECTING" file1 a only in second statement.


    The join statements align cursors which return ALL in the alignment.

    The from statement returns only those that are in tablexxxxx.

    I would need to do a map to show an example.

    Read your own post two or three times.
    Then if you need I'll do a visio post

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