Hi, I found this code that I can't 2

[mimi2]

Hi, I found this code that I can't understand
<cfquery name=&quot;qGetBid&quot; datasource=&quot;#application.ds#&quot;>
select id from billing where
0 = 0
<cfloop list=&quot;#dbfields#&quot; index=&quot;i&quot;>
<cfif len(evaluate(i))>
and #i# = '#evaluate(i)#'
</cfif>
</cfloop>
</cfquery>

What's this &quot;0 = 0&quot; ?
Thanks

 

[MrSki]

Setting a WHERE attribute such as 0=0 insures your query will return every record in the database. Mitch Duszynski
Web Developer
Human Kinetics
PO Box 5076, Champaign, IL 61825
Tel: 217-351-5076 x2474 | Fax: 217-351-2674
mitchd@hkusa.com |

http://www.humankinetics.com

 

[MorganGreylock]

This is a very common thing when using dynamic queries. Heres why:

You can have multiple 'AND' condition statements, but only ONE 'WHERE' clause. People can 'use up' the WHERE clause with 0=0 (always true) and then use dynamic looping to always check 'AND x=y AND a=b, AND r=s, etc.

While it's possible to do it the other way, it's much more work since you have to check which where clause is the first, and use where, and otherwise use AND...

Hope that explains it a bit more.
MG

 

[mimi2]

Thanks