PLz help me in writing query for case statement
Plz give more info
To BigChris's point, please read http://www.cognoise.com/index.php/topic,24030.0.html (http://www.cognoise.com/index.php/topic,24030.0.html).
You've not given any substantive information, really. And I hope you are not trying to write raw SQL - that is not at all a good use of Cognos.