Convert ASCII strings to the number value groups?

  • Please help me, my ignorance of SQL and ASCII has lead me to lose temendous amount of time trying to do this task.

    I have ascii characters in an existing table column that range from single characters to sequentially doubled and tripled characters in range from 0 - 255. My goal is to read each string from each record and convert each charter in that string to it's number equivalent, group the numbers for the string and update another column in the same table with the number. ASCII strings (shown here separated by commas) like. '"/, aA╢, a8σ, %┐,{ '}{

    I found this in SQL Server (ASCII convertion) help topic: ms-help://MS.SQLCC.v9/MS.SQLSVR.v9.en/tsqlref9/html/45c2044a-0593-4805-8bae-0fad4bde2e6b.htm

    But I'm SQL stupid and don't know how to loop, convert, group the values then pass the result back to the table in integer form.

    Below is what I've been trying to modify to accomplish this task and not getting anywhere.

    SET TEXTSIZE 0

    -- Create variables for the character string and for the current

    -- position in the string.

    DECLARE @position int, @string char(8), @myval int

    -- Initialize the current position and the string variables.

    SET @position = 1

    --here I'm trying to load the @string with a select statement ASCII string column

    SET @string = SELECT dbo.FCCFRE.LIC_ID

    FROM dbo.FCCFRE

    --I want to update this column with the numeric value after it resolves the ASCII string to an integer string.

    --I know this code puts out each code separately, but I need to group the values.

    FOR UPDATE OF FRE_ID

    --need to loop through each record but not know how to do it

    WHILE @position <= DATALENGTH(@string)

    BEGIN

    SELECT ASCII(SUBSTRING(@string, @position, 1)),

    CHAR(ASCII(SUBSTRING(@string, @position, 1)))

    SET @position = @position + 1

    END

    GO

    --Don't know how to pass the number to @Myval and update the FRE_ID column.

    This forum is my last resort... Please let me know if this is too difficult for this forum.

    TIA

  • Does this help you out?

    declare @STR varchar(8000);

    set @STR = 'qothobnslfdnoweavnivmnqpwf';

    ;WITH

    TENS (N) AS (SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0 UNION ALL

    SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0 UNION ALL

    SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0 UNION ALL SELECT 0),

    THOUSANDS (N) AS (SELECT 1 FROM TENS t1 CROSS JOIN TENS t2 CROSS JOIN TENS t3),

    MILLIONS (N) AS (SELECT 1 FROM THOUSANDS t1 CROSS JOIN THOUSANDS t2),

    TALLY (N) AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM MILLIONS)

    SELECT N,

    LetterAsPosition = substring(@str, N, 1),

    AsciiAtPosition = ascii(substring(@str, N, 1))

    FROM TALLY

    WHERE N <= datalength(@str)

    ORDER BY N;

    Wayne
    Microsoft Certified Master: SQL Server 2008
    Author - SQL Server T-SQL Recipes


    If you can't explain to another person how the code that you're copying from the internet works, then DON'T USE IT on a production system! After all, you will be the one supporting it!
    Links:
    For better assistance in answering your questions
    Performance Problems
    Common date/time routines
    Understanding and Using APPLY Part 1 & Part 2

  • Thanks very much for your post.

    This a good start but, I put in "!+" for the string and the ascii function thinks that the string

    is"!*". the ascii function stops at 127.

    Is there a way to do this for the entire range of 0-255?

    Thanks for sharing your knowledge!

  • SQL Dummy-659258 (10/27/2010)


    the ascii function stops at 127.

    Actually, it doesn't. You just can't pass the ASCII function more than one character at a time.

    --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)

  • Here's the hard part... what do you want to display for the value aA¦

    --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)

  • Never mind... can't wait for an answer. Here's 95% of the solution. All you have to do is figure out how you actually want to format the 0-255 numbers in the final column. Do note that the ASCII function works just fine for characters over 127. You just have to be careful to only pass it 1 character at a time.

    --=============================================================================

    -- Create some test data. This is NOT a part of the solution

    --=============================================================================

    --===== Conditionally drop the test table to make reruns easier

    IF OBJECT_ID('tempdb..#MyHead','U') IS NOT NULL

    DROP TABLE #MyHead

    ;

    --===== Build and populate the test table on the fly

    WITH

    cteBuild3CharData AS

    ( --=== Builds 3 random characters and a random 1-3 length

    SELECT TOP 100000

    WierdData = CAST(CHAR(ABS(CHECKSUM(NEWID()))%256) AS VARCHAR(3))

    + CAST(CHAR(ABS(CHECKSUM(NEWID()))%256) AS VARCHAR(3))

    + CAST(CHAR(ABS(CHECKSUM(NEWID()))%256) AS VARCHAR(3)),

    RandomLen = ABS(CHECKSUM(NEWID()))%3+1

    FROM sys.all_columns ac1,

    sys.all_columns ac2

    ) --=== Use the random length to determine how long a string to save

    -- and put it all in the test table

    SELECT WierdData = SUBSTRING(WierdData,1,RandomLen)

    INTO #MyHead

    FROM cteBuild3CharData

    ;

    --=============================================================================

    -- In the absence of clear requirements, solve most of the problem.

    --=============================================================================

    --===== Display the Original data and 0-255 for each available character

    SELECT WierdData,

    Character1 = ASCII(SUBSTRING(WierdData,1,1)),

    Character2 = ASCII(SUBSTRING(WierdData,2,1)),

    Character3 = ASCII(SUBSTRING(WierdData,3,1))

    FROM #MyHead

    ;

    --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)

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