Removing nonnumerical data out of a number + SQL

Question

I\'m trying find the best way to remove nonnumerical data from a varchar in SQL e.g.

\'(082) 000-0000\' to \'0820000000\' or
\'+2782 000 0000\' to \'0820000000\'         


        

Answer 1

If you're using SQL Server 2005 or newer then your best option is to create a user-defined CLR function and use a regular expression to remove all non-numeric characters.

If you don't want to use a CLR function then you could create a standard user-defined function. This will do the job although it won't be as efficient:

CREATE FUNCTION dbo.RemoveNonNumerics(@in VARCHAR(255))
RETURNS VARCHAR(255)
AS
BEGIN
    DECLARE @out VARCHAR(255)

    IF (@in IS NOT NULL)
    BEGIN
        SET @out = ''

        WHILE (@in <> '')
        BEGIN
            IF (@in LIKE '[0-9]%')
                SET @out = @out + SUBSTRING(@in, 1, 1)

            SET @in = SUBSTRING(@in, 2, LEN(@in) - 1)
        END
    END

    RETURN(@out)
END

And then select from your table like so:

SELECT dbo.RemoveNonNumerics(your_column) AS your_tidy_column
FROM your_table