Question

I need to remove numbers from a name field in a SELECT query. The numbers are likely to be at the end of the string. Examples would be as follows:

Some Name
Namewithnospace
NamewithInt 100   <--- I want to remove this int from the string

I cannot guarantee that the first part of the string won’t contain a space, although I can be fairly sure that the number will be the last part of the string. Also most of the data won’t have a space.

I can see that there must be a solution using REVERSE() and SUBSTRING() but can’t work out how not to mangle the data that either has no spaces, or those that have a space but no integer.

edit: below is the definition for the MySQL C function that Ollie pointed me towards, with a change made by me to the regexp (to include spaces and punctuation in the function’s output):

DELIMITER !

DROP FUNCTION IF EXISTS alphas! 

CREATE FUNCTION alphas ( str VARCHAR(255) ) 
               RETURNS VARCHAR(255) 
               DETERMINISTIC
BEGIN 
  DECLARE i, len SMALLINT DEFAULT 1; 
  DECLARE ret VARCHAR(255) DEFAULT ''; 
  DECLARE c VARCHAR(1); 
  SET len = CHAR_LENGTH( str ); 
  REPEAT 
    BEGIN 
      SET c = MID( str, i, 1 ); 
      IF c REGEXP '[[:alpha:]]' OR c REGEXP '[[:space:]]' THEN 
        SET ret=CONCAT(ret,c); 
      END IF; 
      SET i = i + 1; 
    END; 
  UNTIL i > len END REPEAT; 
  RETURN ret; 
END !
DELIMITER ; 

Answer 1

Make yourself this stored function called alphas. It goes through the characters of its input text string one by one and removes all the digits.

DELIMITER !

DROP FUNCTION IF EXISTS alphas! 

CREATE FUNCTION alphas ( str VARCHAR(255) ) 
                   RETURNS VARCHAR(255) 
                   DETERMINISTIC
BEGIN 
  DECLARE i, len SMALLINT DEFAULT 1; 
  DECLARE ret VARCHAR(255) DEFAULT ''; 
  DECLARE c VARCHAR(1);   /* NOT CHAR!  NOT CHAR! NOT CHAR! */ 
  SET len = CHAR_LENGTH( str ); 
  REPEAT 
    BEGIN 
      SET c = MID( str, i, 1 ); 
      IF NOT c REGEXP '[[:digit:]]' THEN 
        SET ret=CONCAT(ret,c); 
      END IF; 
      SET i = i + 1; 
    END; 
  UNTIL i > len END REPEAT; 
  RETURN ret; 
END !
DELIMITER ; 

Then do this.

 SELECT alphas(column) AS alphacolumn

Here’s a useful resource from which I cribbed this function.
http://www.artfulsoftware.com/infotree/qrytip.php?id=815