How to remove any trailing numbers from a string?

Question

Sample inputs:

"Hi there how are you"

"What is the #1 pizza place in NYC?"

"Dominoes is number 1"

"Blah blah 123123"

"More blah 12321 123123 123132"

Expected output:

"Hi there how are you"

"What is the #1 pizza place in NYC?"

"Dominoes is number"

"Blah blah"

"More blah"

I'm thinking it's a 2 step process:

1. Split the entire string into characters, one row per character (including spaces), in reverse order
2. Loop through, and for each one if it's a space or a number, skip, otherwise add to the start of another array.

And i should end up with the desired result.

I can think of a few quick and dirty ways, but this needs to perform fairly well, as it's a trigger that runs on a busy table, so thought i'd throw it out to the T-SQL pros.

Any suggestions?

Answer 1

This solution should be a bit more efficient because it first checks to see if the string contains a number, then it checks to see if the string ends in a number.

 CREATE FUNCTION dbo.trim_ending_numbers(@columnvalue AS VARCHAR(100)) RETURNS VARCHAR(100)
    BEGIN
    --This will make the query more efficient by first checking to see if it contains any numbers at all
    IF @columnvalue NOT LIKE '%[0-9]%'
        RETURN @columnvalue

    DECLARE @counter INT
    SET @counter = LEN(@columnvalue)

    IF ISNUMERIC(SUBSTRING(@columnvalue,@counter,1)) = 0
        RETURN @columnvalue 

    WHILE ISNUMERIC(SUBSTRING(@columnvalue,@counter,1)) = 1 OR SUBSTRING(@columnvalue,@counter,1) = ' '
    BEGIN
        SET @counter = @counter -1
        IF @counter < 0
            BREAK
    END
    SET @columnvalue = SUBSTRING(@columnvalue,0,@counter+1)

    RETURN @columnvalue
    END

If you run

SELECT dbo.trim_ending_numbers('More blah 12321 123123 123132')

It will return

'More blah'