Question

I am using Oracle Database 11g Enterprise Edition Release 11.2.0.2.0

I have a table as follows:

Table1:
Name              Null     Type          
----------------- -------- ------------- 
NAME              NOT NULL VARCHAR2(64)  
VERSION           NOT NULL VARCHAR2(64) 


Table1
Name    Version
---------------
A         1
B         12.1.0.2
B         8.2.1.2
B         12.0.0
C         11.1.2
C         11.01.05

I want the output as:

Name    Version
---------------
A        1
B        12.1.0.2
C        11.01.05

Basically, I want to get the row for each name which have highest version. For this I am using the following query:

SELECT t1.NAME, 
       t1.VERSION
FROM TABLE1 t1 
LEFT OUTER JOIN TABLE1 t2
on (t1.NAME = t2.NAME and t1.VERSION < t2.VERSION)
where t2.NAME is null

Now ‘t1.VERSION < t2.VERSION’ only works in normal version cases but in cases such as:

B         12.1.0.2
B         8.2.1.2

It fails, I need a PL/SQL script to normalize the version strings and compare them for higher value.

Answer 1

Just wrote a MySQL user defined function to accomplish the task, you can easily port it to ORACLE PL/SQL.

DELIMITER $$

DROP FUNCTION IF EXISTS `VerCmp`$$

CREATE FUNCTION VerCmp (VerX VARCHAR(64), VerY VARCHAR(64), Delim CHAR(1))
RETURNS INT DETERMINISTIC
BEGIN
    DECLARE idx INT UNSIGNED DEFAULT 1;
    DECLARE xVer INT DEFAULT 0;
    DECLARE yVer INT DEFAULT 0;
    DECLARE xCount INT UNSIGNED DEFAULT 0;
    DECLARE yCount INT UNSIGNED DEFAULT 0;
    DECLARE counter INT UNSIGNED DEFAULT 0;

SET xCount = LENGTH(VerX) - LENGTH(REPLACE(VerX, Delim,'')) +1;
SET yCount = LENGTH(VerY) - LENGTH(REPLACE(VerY, Delim,'')) +1;

IF xCount > yCount THEN
    SET counter = xCount;
ELSE
    SET counter = yCount;
END IF;

WHILE (idx <= counter) DO

    IF (xCount >= idx) THEN
        SET xVer = SUBSTRING_INDEX(SUBSTRING_INDEX(VerX, Delim, idx), Delim, -1) +0;
    ELSE
        SET xVer =0;
    END IF;
    IF (yCount >= idx) THEN
        SET yVer = SUBSTRING_INDEX(SUBSTRING_INDEX(VerY, Delim, idx), Delim, -1) +0;
    ELSE 
        SET yVer = 0;
    END IF;

    IF (xVer > yVer) THEN
        RETURN 1;
    ELSEIF (xVer < yVer) THEN
        RETURN -1;
    END IF;

    SET idx = idx +1;
END WHILE;

RETURN 0;

END$$;

DELIMITER ;

Few test that I ran:

select vercmp('5.2.4','5.2.5','.');
+------------------------------+
| vercmp('5.2.4','5.2.5','.')  |
+------------------------------+
|                           -1 |
+------------------------------+

select vercmp('5.2.4','5.2.4','.');
+------------------------------+
| vercmp('5.2.4','5.2.4','.')  |
+------------------------------+
|                            0 |
+------------------------------+

select vercmp('5.2.4','5.2','.');
+----------------------------+
| vercmp('5.2.4','5.2','.')  |
+----------------------------+
|                          1 |
+----------------------------+

select vercmp('1,2,4','5,2',',');
+----------------------------+
| vercmp('1,2,4','5,2',',')  |
+----------------------------+
|                         -1 |
+----------------------------+