Handling larger strings in Sql Server 2008

Question

We have an stored procedure that we created so that user can write comma separated search tags in their software product's admin. So he can add comma-separated tags and in case if he wants to edit them, we read from the table all the tags, recreate them as comma-separated values (CSV) in stored procedure and returns that to the calling code. What happened recently, the user complained that he could not see the new CSVs he wrote. I looked into it and found out that the stored procedure is truncating the string when it reads values from database and creates CSV string. The string is of type nvarchar, and because its exceeding the max characters of 4000 limit, the values gets truncated. Any ideas on how to work out that problem.

Find my code underneath.

BEGIN
BEGIN 
    Declare @Synonyms Table
    (
        RowID int Identity(1,1),
        SynonymID int,
        [Synonym] nvarchar(4000)
    );

    SET NOCOUNT ON;

    Insert @Synonyms(SynonymID, [Synonym])
    Select distinct SynonymID, [Synonym] From RF_SearchSynonyms with(nolock) Where SearchTermID = @SearchTermID And ActiveInd = 1

    If((Select COUNT(RowID) From @Synonyms) <> 0)
    BEGIN
        Declare @CurrentRow int = (Select MIN(RowID) From @Synonyms),
                @TotalRows int = (Select MAX(RowID) From @Synonyms),
                @Synonyms_CSV nvarchar(4000) = '';


        WHILE @CurrentRow <= @TotalRows
        BEGIN
            Declare @TempSyn nvarchar(500);
            Select @TempSyn = [Synonym] + ',' From @Synonyms Where RowID = @CurrentRow;
            Set @Synonyms_CSV = @Synonyms_CSV + LTRIM(RTRIM(LOWER(@TempSyn)));

            SET @CurrentRow = @CurrentRow + 1
        END
    END
    Else
    BEGIN
        Set @Synonyms_CSV = '';
    END
END

BEGIN
    Declare @SKUs Table
    (
        RowID int Identity(1,1),
        SkuID int,
        SKU nvarchar(15)
    );

    SET NOCOUNT ON;

    Insert @SKUs(SkuID, SKU)
    Select distinct SkuID, SKU From RF_SearchSkus with(nolock) Where SearchTermID = @SearchTermID And ActiveInd = 1

    If((Select COUNT(RowID) From @SKUs) <> 0)
    BEGIN
        Declare @CurrentRow1 int = (Select MIN(RowID) From @SKUs),
                @TotalRows1 int = (Select MAX(RowID) From @SKUs),
                @Skus_CSV nvarchar(4000) = '';


        WHILE @CurrentRow1 <= @TotalRows1
        BEGIN
            Declare @TempSku nvarchar(15);
            Select @TempSku = SKU + ',' From @SKUs Where RowID = @CurrentRow1;
            Set @Skus_CSV = @Skus_CSV + LTRIM(RTRIM(@TempSku));

            SET @CurrentRow1 = @CurrentRow1 + 1
        END
    END
    Else
    BEGIN
        Set @Skus_CSV = '';
    END
END

BEGIN
    Declare @Combined varchar(8000),
            @syn_len int = 0,
            @sku_len int = 0;

    Select @syn_len = LEN(@Synonyms_CSV);
    Select @sku_len = LEN(@Skus_CSV);
    Select @Combined = @Synonyms_CSV + '-_-' + @Skus_CSV;

    Select @Synonyms_CSV + '-_-' + @Skus_CSV;
END

END

I can't use text and ntext as they do not play nice with concatenation operations.

Thanks.

3Dave · Accepted Answer · 2010-12-20 23:17:05Z

3

How are your declaring the string parameter?

nvarchar(max)

supports up to 2^32-1 (2GB)

See this link.

edited Dec 20, 2010 at 23:17

answered Dec 20, 2010 at 22:27

3Dave

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3 Comments

Ashar Syed Over a year ago

I am using nvarchar(max) which supports character length max upto 4000. Its truncating the rest which exceeds the 4000 limit. Find my code in the post I just edited.

3Dave Over a year ago

@Ashar nvarchar(max) doesn't have a 4k limit. See the link I posted. Your code declares the column [synonym] as nvarchar(4000), so of course it's truncate to 4000.

Ashar Syed Over a year ago

Oh thanks, yeah that worked, I had read the max nvarchar can take is alpha-numeric characters upto 4000 and thats why I ended up declaring variable of length upto 4000. My bad. Thanks David. You are my hero :)

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