QRandom Support

[enzo]

This patch include the possibility to get data in random order.

I based on zcodo change at  http://code.google.com/p/zcodo/source/browse/trunk/wwwroot/includes/qcodo/_core/framework/QQuery.class.php?spec=svn52&r=52

Thread discussing this:  http://qcu.be/content/how-do-i-create-random-output-query#comment-790

Just remember order random in big tables could be a bad idea.

[alex94040]

No new features can be added to the 1.0 branch now. This is a cool enhancement - thanks for the contribution - but it'll have to wait until 1.1.

[alex94040]

Question: is the RAND() function supported by every single database adapter? I don't want to introduce QQuery components that are database vendor-specific.

[agsel]

RAND() is basically used only in MySQL. You can check  http://www.petefreitag.com/item/466.cfm for random usage in different databases. Though the site has examples for ordering by random, it still gives you the idea.

[alex94040]

Since this is MySQL-specific, this cannot go into QQuery. MySQL users will have to write manual SQL statement queries to do this. Unless there's a vendor-independent way to do this, I will be closing this bug as a "won't fix".

[VexedPanda]

I think the line is more "can other DBs do the same thing", not "do they use the same syntax". Our database abstraction layer should be able to handle it the same way the limit clause is handled.

This is significantly more work, but seems like a valid improvement to me.