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  1. #1
    Join Date
    Mar 2004
    Posts
    128

    Unanswered: calculate difference between rows (was "Sql")

    Hi all,
    If I have the table:

    Date/Time DeviceNumber X
    2/12/04 07:15:15 40 20
    2/12/04 12:10:02 40 60
    2/12/04 17:56:03 40 100
    3/12/04 06:12:24 40 500
    3/12/04 08:19:15 40 700

    How I can calculate the difference of X where the first X was at the minimum time in 3/12/04 and the second X was at the minimum time in 2/12/04.

    I mean the two rows:
    3/12/04 06:12:24 40 500
    2/12/04 07:15:15 40 20

    The X difference is: 480

    Please help
    Thanks...

  2. #2
    Join Date
    Aug 2004
    Posts
    330
    Is it me, or does this seem like deja vu.


    Try:

    Select sum(xx)
    from(
    select x as xx
    from table
    where Date/Time = (select max(Date/Time) from table)
    union
    select multiply(x,-1) as xx
    from table
    where Date/Time = (select min(Date/Time) from table)
    )

    The syntax will have to be modified to fit your DBMS and correct any errors i may have included.
    Last edited by urquel; 12-03-04 at 11:26.

  3. #3
    Join Date
    Sep 2002
    Location
    UK
    Posts
    5,171
    Provided Answers: 1
    Quote Originally Posted by urquel
    Is it me, or does this seem like deja vu.
    Yes, this question does seem to be posted on a daily basis at the moment!

  4. #4
    Join Date
    Feb 2004
    Location
    In front of the computer
    Posts
    15,579
    Provided Answers: 54
    Quote Originally Posted by urquel
    Is it me, or does this seem like deja vu.
    As George Carlin put it, "It's not just Deja Vu, it is Deja Vu all over again!"

    -PatP

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