AR condition and null value

When request is something like


$q = Mdl::model()->findAll('a = :a',array(':a'=>null));

, sql is


select * from mdl where a = NULL

, but must be


select * from mdl where a is NULL

.

Or there is any ways to use ‘is’ instead ‘=’ ?


$q = Mdl::model()->findAllByAttributes(array('a' => null));

But you could freely use ‘is’ as well.

Thanx, but ‘is’ is used only with null value :)