active record - simple mysql statement but not working

[eluser]CI MikeD[/eluser]
Is it something I am missing here? Here is the part of the sql statement built with active record that is getting errors:

$this->db->where('DATE_ADD(CURRENT_DATE,INTERVAL 1 DAY)', 'ending');

CI returnes this error: An Error Was Encountered, Error Number: 1064

with this created part of mysql:

Code:

DATE_ADD(CURRENT_DATE,INTERVAL 1 DAY) 'ending'

So it fails to create equal sign (=). If I force the creation of = sign like this:

$this->db->where('DATE_ADD(CURRENT_DATE,INTERVAL 1 DAY)=', 'ending');

the error is the same event though query looks ok now. The most "funny" thing about all this is while CI reports error when i copy paste entire generated mysql to phpmyadmin it works.

above is only part of mysql query. any ideas?thanks.