SQL query: How can I get the corresponding employee id which are not allotted to department?

I have Employee and Department table. How can I get the corresponding employee id which are not allotted to department?

Employee Table      department table    AllocatedDetails
EmpID               DeptID              All开发者_如何转开发ocatedID
Name                Name                EmpID

Now I have to retrieve the EmpID which is not in the table AllocatedDetails.

Can anyone help me please.....

Note: I need SQL query only

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select empid, name
from employee
where empid not in (select empid from allocatedDetails)

Note this assumes the allocatedid is a deptid