How to validate a comma separated string using array in SQL

Question

I have to create a function in sql which will validate a comma separated string.

example: string will be like @str = \'AB,CD,EF,GH\'

I have

Answer 1

This function will take your comma separated list and return a table, just like STRING_SPLIT() which I think is only available for SQL Server 2016. Then, you'll just INNER JOIN to the table based on your conditions. I usually set a table variable to the results of this function so I can reuse it.

ALTER FUNCTION [dbo].[ufn_split_string]
(    
    @RowData NVARCHAR(MAX),
    @Delimeter NVARCHAR(MAX)
)
RETURNS @RtnValue TABLE 
(
    ID INT IDENTITY(1,1),
    DataRow NVARCHAR(MAX)
) 
AS
BEGIN 
    DECLARE @Iterator INT
    SET @Iterator = 1

    DECLARE @FoundIndex INT
    SET @FoundIndex = CHARINDEX(@Delimeter,@RowData)

    WHILE (@FoundIndex>0)
    BEGIN
        INSERT INTO @RtnValue (DataRow)
        SELECT 
            Data = LTRIM(RTRIM(SUBSTRING(@RowData, 1, @FoundIndex - 1)))

        SET @RowData = SUBSTRING(@RowData, 
                @FoundIndex  + 1,
                LEN(@RowData))

        SET @Iterator = @Iterator + 1
        SET @FoundIndex = CHARINDEX(@Delimeter, @RowData)
    END

    INSERT INTO @RtnValue (DataRow)
    SELECT Data = LTRIM(RTRIM(@RowData))

    RETURN
END

GO