sharepoint 2010 use fulltextsearch query to search user profile

Hello all,

I have a problem with FullTextSearch query for user profile:

I have the query below:

SELECT PictureURL, TitleOfPersonal, PersonalTitle,  Lastname, Firstname, AccountName, JobTitle, Department, workemail, EmployeeID, Empid, Exten, LeftDate, JoinDate

FROM SCOPE() WHERE "scope"='People' AND (Department = 'CEO Office' OR Department = 'Marketing & Business Development Department' OR Department = 'Medical Department' OR Department = 'Finance Department' OR Department = 'COO Office' OR Department = 'Document Management & Translation Department') AND  empID != '' ORDER BY LastName

But this query does not return any result! 

Could someone help me on this ?

Thank you very much !