Comments on: MySQL: Number + NULL = NULL http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/ Tech Thoughts, Mostly on LAMP - by Jon Haddad Thu, 22 Jul 2010 09:10:54 -0700 http://wordpress.org/?v=2.8.4 hourly 1 By: Jihad http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-18438 Jihad Fri, 11 Apr 2008 22:38:15 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-18438 Very helpful, thanks a lot Very helpful, thanks a lot

]]> By: Stabbquadd http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-9029 Stabbquadd Mon, 16 Jul 2007 17:17:10 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-9029 Thanx for writting this, you nearly saved my ass ! Thanx for writting this, you nearly saved my ass !

]]> By: JTW http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-7729 JTW Fri, 08 Jun 2007 14:19:22 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-7729 1. some expressions like GREATEST() return different results on different versions of MySQL. SELECT GREATEST(0,NULL); returns 0 on 4.1 and NULL on 5.0. 2. to CONCAT with NULL values, use CONCAT_WS('', ...). The first parameter is a delimiter and in this case, it's just an empty string. 1. some expressions like GREATEST() return different results on different versions of MySQL.

SELECT GREATEST(0,NULL); returns 0 on 4.1 and NULL on 5.0.

2. to CONCAT with NULL values, use CONCAT_WS(”, …). The first parameter is a delimiter and in this case, it’s just an empty string.

]]> By: Julius http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-5268 Julius Sun, 06 May 2007 13:11:38 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-5268 Just spend almost an hour trying to figure out what to do in case my subquery returned null - found your IFNULL() solution on google, and it solves my problem perfectly! Thanks :-) Just spend almost an hour trying to figure out what to do in case my subquery returned null – found your IFNULL() solution on google, and it solves my problem perfectly! Thanks :-)

]]> By: Mark http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-4469 Mark Wed, 14 Mar 2007 20:37:31 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-4469 Thanks for this. I was having the same problem. Maybe should have realized it, but it makes me feel good that I'm the first to be bit. Also Xaprb, thanks for COALESCE() - I never really understood what it would be good for. Thanks for this. I was having the same problem. Maybe should have realized it, but it makes me feel good that I’m the first to be bit. Also Xaprb, thanks for COALESCE() – I never really understood what it would be good for.

]]> By: IJay http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-4053 IJay Wed, 21 Feb 2007 02:47:13 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-4053 Just found this in Google. Thank you for that article. I just wish I would have found this earlier. Would have saved me some hours. I had the same problem ("Why the heck is 10 + NULL not 10?"). Now I've got a good solution. Thanks. Just found this in Google. Thank you for that article. I just wish I would have found this earlier. Would have saved me some hours. I had the same problem (”Why the heck is 10 + NULL not 10?”). Now I’ve got a good solution. Thanks.

]]> By: Brandon Drury http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-1780 Brandon Drury Thu, 30 Nov 2006 19:51:49 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-1780 It appears that NULL does not work this way in PHP, however. It appears that NULL does not work this way in PHP, however.

]]> By: jon http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-31 jon Fri, 22 Sep 2006 03:08:33 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-31 And sheeri, you are wrong anyway. mysql> select concat(4,5); +-------------+ | concat(4,5) | +-------------+ | 45 | +-------------+ And sheeri, you are wrong anyway.

mysql> select concat(4,5);
+————-+
| concat(4,5) |
+————-+
| 45 |
+————-+

]]> By: jon http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-29 jon Fri, 22 Sep 2006 01:18:16 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-29 Sheeri: Mine is a practical real world example. I realize that there can be multiple solutions to a given problem. Thanks. Sheeri: Mine is a practical real world example. I realize that there can be multiple solutions to a given problem. Thanks.

]]> By: Sheeri http://www.rustyrazorblade.com/2006/09/mysql-number-null-null/comment-page-1/#comment-28 Sheeri Fri, 22 Sep 2006 01:07:52 +0000 http://www.rustyrazorblade.com/index.php/2006/09/20/mysql-number-null-null/#comment-28 1) CONCAT has the same functionality 2) You do not need a table to demonstrate either point mysql> select 1+NULL+1; +----------+ | 1+NULL+1 | +----------+ | NULL | +----------+ 1 row in set (0.00 sec) mysql> select concat('a','b'); +-----------------+ | concat('a','b') | +-----------------+ | ab | +-----------------+ 1 row in set (0.00 sec) mysql> select concat('a',NULL,'b'); +----------------------+ | concat('a',NULL,'b') | +----------------------+ | | +----------------------+ 1 row in set (0.00 sec) 1) CONCAT has the same functionality
2) You do not need a table to demonstrate either point

mysql> select 1+NULL+1;
+———-+
| 1+NULL+1 |
+———-+
| NULL |
+———-+
1 row in set (0.00 sec)

mysql> select concat(’a',’b');
+—————–+
| concat(’a',’b') |
+—————–+
| ab |
+—————–+
1 row in set (0.00 sec)

mysql> select concat(’a',NULL,’b');
+———————-+
| concat(’a',NULL,’b') |
+———————-+
| |
+———————-+
1 row in set (0.00 sec)

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