String Split and LEFT OUTER JOIN in Two Tables

  • Hello Everyone

    I am working on an issue that involves string splitting. It really bothers me that people will Not design a database correctly, and ends up storing a delimited list in a single column.

    I do have the function named "DelimitedSplit8K" I love that function.

    The thing I am working on is that I need to split two different strings, place the now "rows" of data into table, each of their own.(Done)

    Using a LEFT OUTER JOIN, select the rows that are in one table, and not in the other.(Need Assistance)

    I know how to use the string splitter, and it works fine. But I am having trouble performing the LEFT OUTER JOIN.

    CREATE TABLE #FirstDataString

    (

    FDataString varchar(250)

    )

    CREATE TABLE #SecondDataString

    (

    SDataString varchar(250)

    )

    INSERT INTO #FirstDataString

    (

    FDataString

    )

    VALUES

    (

    '1,3,6,8,9,10,12,13,15,16,20,21,24,26,28,31,33,34,35,49,51,52,53,57,58,61,63,66,69,70,71,75,76,77,78,79,81,82,85,88,90,91,92,93,94,95,96,97,98,99,100,105,107,110,111,112,118,122,124,125'

    )

    INSERT INTO #SecondDataString

    (

    SDataString

    )

    VALUES

    (

    '1,3,5,8,9,10,13,15,16,20,24,26,28,31,33,35,49,51,52,57,58,61,63,69,70,75,76,77,78,79,81,85,88,90,91,92,94,95,96,97,98,100,105,110,111,118,122,125'

    )

    SELECT Item AS FirstItem

    FROM #FirstDataString f

    CROSS APPLY dbo.DelimitedSplit8k(F.FDataString,',') split

    SELECT Item AS SecondItem

    FROM #SecondDataString s

    CROSS APPLY dbo.DelimitedSplit8k(S.SDataString,',') split

    DROP TABLE dbo.#FirstDataString;

    DROP TABLE dbo.#SecondDataString;

    I hope that someone can assist me with this query. I feel that I am close, but something is just not making it, and I cannot figure that part out.

    Thank You in advance for all your assistance, comments and suggestions.

    Andrew SQLDBA

  • Misread OP. Comment removed.:blush:

    "I cant stress enough the importance of switching from a sequential files mindset to set-based thinking. After you make the switch, you can spend your time tuning and optimizing your queries instead of maintaining lengthy, poor-performing code."

    -- Itzik Ben-Gan 2001

  • Hi

    A couple of other options, NOT EXISTS and FULL OUTER JOIN

    CREATE TABLE #FirstDataString

    (

    FDataString varchar(250)

    )

    CREATE TABLE #SecondDataString

    (

    SDataString varchar(250)

    )

    INSERT INTO #FirstDataString

    (

    FDataString

    )

    VALUES

    (

    '1,3,6,8,9,10,12,13,15,16,20,21,24,26,28,31,33,34,35,49,51,52,53,57,58,61,63,66,69,70,71,75,76,77,78,79,81,82,85,88,90,91,92,93,94,95,96,97,98,99,100,105,107,110,111,112,118,122,124,125'

    )

    INSERT INTO #SecondDataString

    (

    SDataString

    )

    VALUES

    (

    '1,3,5,8,9,10,13,15,16,20,24,26,28,31,33,35,49,51,52,57,58,61,63,69,70,75,76,77,78,79,81,85,88,90,91,92,94,95,96,97,98,100,105,110,111,118,122,125'

    )

    SELECT Item AS FirstItem

    FROM #FirstDataString f

    CROSS APPLY dbo.DelimitedSplit8k(F.FDataString,',') splitf

    WHERE NOT EXISTS (

    SELECT Item AS SecondItem

    FROM #SecondDataString s

    CROSS APPLY dbo.DelimitedSplit8k(S.SDataString,',') splits

    WHERE splitf.item = splits.item)

    SELECT Item AS SecondItem

    FROM #SecondDataString s

    CROSS APPLY dbo.DelimitedSplit8k(S.SDataString,',') splits

    WHERE NOT EXISTS (

    SELECT Item AS FirstItem

    FROM #FirstDataString f

    CROSS APPLY dbo.DelimitedSplit8k(F.FDataString,',') splitf

    WHERE splitf.item = splits.item)

    SELECT fs.FirstItem, ss.SecondItem

    FROM (

    SELECT Item AS FirstItem

    FROM #FirstDataString f

    CROSS APPLY dbo.DelimitedSplit8k(F.FDataString,',') splitf) fs

    FULL OUTER JOIN

    (

    SELECT Item AS SecondItem

    FROM #SecondDataString s

    CROSS APPLY dbo.DelimitedSplit8k(S.SDataString,',') splits) ss ON fs.FirstItem = ss.SecondItem

    WHERE fs.FirstItem is null or ss.SecondItem is null

    GO

    DROP TABLE dbo.#FirstDataString;

    DROP TABLE dbo.#SecondDataString;

  • If you want to return a number if it appears in either table but not in the other, I don't think EXCEPT will work.

    Not sure if my interpretation is correct, but if it is this will do it.

    SELECT Item

    FROM

    (

    SELECT Item

    FROM #FirstDataString a

    CROSS APPLY dbo.DelimitedSplit8k(FDataString,',')

    UNION ALL

    SELECT Item

    FROM #SecondDataString s

    CROSS APPLY dbo.DelimitedSplit8k(SDataString,',')

    ) a

    GROUP BY Item

    HAVING COUNT(*) = 1;

    This returns 14 rows whereas EXCEPT returns 13.


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    My thought question: Have you ever been told that your query runs too fast?

    My advice:
    INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
    The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

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  • Thank You to everyone that gave their code, comments and suggestions. They all worked really well.

    How would I add a bit column and fill it with a 1 if the values were in both tables, and a 0 if the Item was not in the first table?

    Thank You in advance

    Andrew SQLDBA

  • On the FULL OUTER join query, a CASE statement would do it.

    SELECT fs.FirstItem, ss.SecondItem,

    CASE WHEN fs.FirstItem = ss.SecondItem THEN 1

    WHEN fs.FirstItem is null THEN 0

    ELSE null END flag

    FROM (

    SELECT Item AS FirstItem

    FROM #FirstDataString f

    CROSS APPLY dbo.DelimitedSplit8k(F.FDataString,',') splitf) fs

    FULL OUTER JOIN

    (

    SELECT Item AS SecondItem

    FROM #SecondDataString s

    CROSS APPLY dbo.DelimitedSplit8k(S.SDataString,',') splits) ss ON fs.FirstItem = ss.SecondItem

    --WHERE fs.FirstItem is null or ss.SecondItem is null

    or if you want to get fancy:-) you could use

    COALESCE(CAST(FirstItem + SecondItem as bit),CAST(FirstItem as bit) - 1)

    Of course you would need to make sure the items are numbers for that one.

    What would you do for items that are not in the second table?

  • Thank You Micky

    I was trying to use a CASE statement, but I had it in the wrong place.

    Greatly appreciate your assistance

    Andrew SQLDBA

  • No problem ... glad to help

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