mysql字段中提取数字

CREATE FUNCTION GetNum (Varstring varchar(50)) RETURNS varchar(30)
DETERMINISTIC
BEGIN
DECLARE v_length INT DEFAULT 0;
DECLARE v_Tmp varchar(50) default '';
set v_length=CHAR_LENGTH(Varstring);
WHILE v_length > 0 DO
IF (ASCII(mid(Varstring,v_length,1))>47 and ASCII(mid(Varstring,v_length,1))<58 )   THEN
set v_Tmp=concat(v_Tmp,mid(Varstring,v_length,1));
END IF;
SET v_length = v_length - 1;
END WHILE;
RETURN REVERSE(v_Tmp);
END;

有些版本下面语句不好使 请用上面语句

DELIMITER $$
 
USE `eps` $$
 
DROP FUNCTION IF EXISTS `fn_GetNum` $$
 
CREATE  FUNCTION `fn_GetNum` (Varstring VARCHAR (500)) RETURNS VARCHAR (30) CHARSET utf8mb4 
BEGIN
  DECLARE v_length INT DEFAULT 0 ;
  DECLARE v_Tmp VARCHAR (50) DEFAULT '' ;
  SET v_length = CHAR_LENGTH(Varstring) ;
  WHILE
    v_length > 0 DO IF (
      ASCII(MID(Varstring, v_length, 1)) > 47 
      AND ASCII(MID(Varstring, v_length, 1)) < 58
    ) 
    THEN SET v_Tmp = CONCAT(v_Tmp, MID(Varstring, v_length, 1)) ;
    END IF ;
    SET v_length = v_length - 1 ;
  END WHILE ;
  RETURN REVERSE(v_Tmp) ;
END $$