Sql Query Analyzer Against Cisco Call Manager DB

Greetings all. New user here. I'm just getting started with using sql query's with our cisco voIP call manager database. Although cisco has a utility "CDR" which runs pre-defined reports; it's not enough. So far there have been several request for specific data which "CDR" cannot compile, in which we have to use analyzer. Unfortunately I'm not versed and need a little help. It's been asked I pull a report from call manager which shows all "forced authorization Codes" cisco calls these client matter codes. Here is the query I tried using. It pulls all user data but the client matter code column is empty. I tried with * and *.* inside brackets as well.

select * from CallDetailRecord where clientmattercode=''

Can anybody help so I can get the records of who has what particular in use client matter code?

thanks to all in advance, I hope to learn as much as possible from the experts.