Re: Converting SQL Dialects
| From: | Matt Neimeyer | Date: | Thu, 23 Jul 2009 19:39:08 +0000 |
| Subject: | Re: Converting SQL Dialects | ||
| References: | 1 2 3 4 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-295773@lists.php.net to get a copy of this message | ||
> You might even be able to convert EMPTY(X) to COALESCE(X, '') = ''.
> MySQL seems to be pretty forgiving with its implicit type-casting.
Hmm... The new system I've written properly handles the datatype and
EMPTY... So this would be a hack to much around with regexs to replace
EMPTY in customer built selects.
Now I fiddled around with this on 5.1.33-community on Windows and I
get the following odd results...
select
coalesce(0,"")=0,coalesce("","")=0,coalesce(0,"")=0,coalesce("","")=0;
returns 1, 1, 1, 1
but...
select
coalesce(0,"")="",coalesce("","")="",coalesce(0,"")="",coalesce("","")="";
returns 0, 1, 0, 1
Which implies that in certain circumstances "" = 0 but 0 != "" (unless
I'm missing something).
Either way it looks like I can use coalesce(X,"")=0 which should be useful!
Matt