Comparison on numeric part of string in MySQL - mysql

Question

I have a field that contains version information such as:
V12.0
V1.0
BE0.50
VV24
I want to query for version greater then n. The number I want to do the comparison on is preceded by a non-fixed number of characters. Is it possible to do something like:
SELECT version FROM table WHERE int_part(version) > 10
V12.0
VV24

Answer 1

In this case it seems that version number appears in end only, alphabets are in beginning. So, probable solution will be to reverse the string, type cast it to get numbers, then reverse back the number obtained.
Try following solution
SELECT version
FROM table
HAVING CAST(REVERSE(IF(LOCATE(".", version), (CAST(REVERSE(version) AS DECIMAL(4,2))), (CAST(REVERSE(version) AS UNSIGNED INTEGER)))) AS DECIMAL(4,2)) > 12;
Hope it helps...

Answer 2

Seem like you have to create you own function to do this:
CREATE FUNCTION IsNumeric (val varchar(255)) RETURNS tinyint
RETURN val REGEXP '^(-|\\+){0,1}([0-9]+\\.[0-9]*|[0-9]*\\.[0-9]+|[0-9]+)$';
CREATE FUNCTION NumericOnly (val VARCHAR(255))
RETURNS VARCHAR(255)
BEGIN
DECLARE idx INT DEFAULT 0;
IF ISNULL(val) THEN RETURN NULL; END IF;
IF LENGTH(val) = 0 THEN RETURN ""; END IF;
SET idx = LENGTH(val);
WHILE idx > 0 DO
IF IsNumeric(SUBSTRING(val,idx,1)) = 0 THEN
SET val = REPLACE(val,SUBSTRING(val,idx,1),"");
SET idx = LENGTH(val)+1;
END IF;
SET idx = idx - 1;
END WHILE;
RETURN val;
END;
select NumericOnly('vv24');
+---------------------+
| NumericOnly('vv24') |
+---------------------+
| 24 |
+---------------------+

Answer 3

Big downside of MySQL not supporting Regular Expressions in REPLACE method. If I have to do any matching of sorts, I usually pull all data to my PHP and process it there. In long run it is better solution. Of course you could always use User Defined Functions if you prefer.
http://dev.mysql.com/doc/refman/5.0/en/adding-udf.html
#shubhansh
Would 24 not change to 0.24 and failed > 12 ?