Question

I am trying to change a string which is in the format say :

"12_7,34_22,28_4,6_22"

TO

"12,34,28,6"

Essentially I want to eliminate “_” (underscore and whatever is after that and before comma ) from the string. Haven’t worked with sql so it is looking like an uphill task to me.

Answer 1

CREATE FUNCTION DeUnderscore(@s nvarchar(max))
RETURNS nvarchar(max)
AS
BEGIN
    DECLARE @iu int = CHARINDEX('_', @s); -- position of _
    DECLARE @ic int = CHARINDEX(',', @s, @iu) -- position of ,  
    WHILE (@iu != 0)
    BEGIN
        IF @ic = 0 SET @ic = LEN(@s) + 1; -- if there's no , go to end of string
        SET @s = STUFF(@s, @iu, @ic - @iu, ''); -- replace everything after _ and before , with ''
        SET @iu = CHARINDEX('_', @s);
        SET @ic = CHARINDEX(',', @s, @iu)
    END 
    RETURN @s
END

..in use it would look like..

SELECT dbo.DeUnderscore(myValue) AS myCleanedValue FROM myTable;