Comments on: Implicit casting you don't want to see around http://code.openark.org/blog/mysql/implicit-casting-you-dont-want-to-see-around Blog by Shlomi Noach Wed, 01 Feb 2012 20:47:51 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Monty Taylor http://code.openark.org/blog/mysql/implicit-casting-you-dont-want-to-see-around/comment-page-1#comment-15598 Monty Taylor Thu, 08 Jul 2010 22:12:25 +0000 http://code.openark.org/blog/?p=2344#comment-15598 ++ I'd also like to point out that passing in your numbers as strings causes the database server to create a Object representing the string value for them and then to convert that into a number which involves a bunch of conversion code. If you just pass it in as a number, then it gets directly shunted into a number in the parser from the protocol. NEVER a good idea to use "3" if you want it to be a number. ++

I'd also like to point out that passing in your numbers as strings causes the database server to create a Object representing the string value for them and then to convert that into a number which involves a bunch of conversion code. If you just pass it in as a number, then it gets directly shunted into a number in the parser from the protocol.

NEVER a good idea to use "3" if you want it to be a number.

]]> By: Giuseppe Maxia http://code.openark.org/blog/mysql/implicit-casting-you-dont-want-to-see-around/comment-page-1#comment-15537 Giuseppe Maxia Wed, 07 Jul 2010 10:25:45 +0000 http://code.openark.org/blog/?p=2344#comment-15537 Excellent advice, Shlomi. For completeness, I should mention that, when using proper date arithmetic syntax, the implicit conversion works as expected. <pre> mysql> SELECT '2010-01-01' + interval 3 day; +-------------------------------+ | '2010-01-01' + interval 3 day | +-------------------------------+ | 2010-01-04 | +-------------------------------+ mysql> SELECT '2010-01-01' - interval 3 day; +-------------------------------+ | '2010-01-01' - interval 3 day | +-------------------------------+ | 2009-12-29 | +-------------------------------+ </pre> Excellent advice, Shlomi.
For completeness, I should mention that, when using proper date arithmetic syntax, the implicit conversion works as expected.

mysql> SELECT '2010-01-01' + interval 3 day;
+-------------------------------+
| '2010-01-01' + interval 3 day |
+-------------------------------+
| 2010-01-04                    |
+-------------------------------+

mysql> SELECT '2010-01-01' - interval 3 day;
+-------------------------------+
| '2010-01-01' - interval 3 day |
+-------------------------------+
| 2009-12-29                    |
+-------------------------------+
]]> By: Mrten http://code.openark.org/blog/mysql/implicit-casting-you-dont-want-to-see-around/comment-page-1#comment-15536 Mrten Wed, 07 Jul 2010 09:51:59 +0000 http://code.openark.org/blog/?p=2344#comment-15536 fun if you combine the knowledge from this post with languages that have no strong type (say, php). fun if you combine the knowledge from this post with languages that have no strong type (say, php).

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