Home Forums SQL Server 2008 SQL Server Newbies mod 10 weights 1, 2 RE: mod 10 weights 1, 2

  • January 7, 2010 at 9:04 pm

    #1100677

    I don't know which will be faster nor which you prefer to read nor am I sure which is correct (I don't subtract my result from 10 like Lynn did... I do it like they do for Luhn Mod 10 Check Sums for Credit Cards).

    The other thing to remember is that if you use such a thing on credit cards, the right-most digit will always be treated as a "1" multiplier and then you work to the left in 1-2 order...

    DECLARE @TestData VARCHAR(12),

    @ControlString CHAR(36)

    SELECT @TestData = '03EA12J78',

    @ControlString = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'

    SELECT SUM(((N+1)%2+1)*(CHARINDEX(SUBSTRING(@TestData, N, 1),@ControlString)-1))%10

    FROM dbo.Tally

    WHERE N <= LEN(@TestData)

    --Jeff Moden

    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.

    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)