请尝试以下操作:
select Emp_ID, F_Name, count(Act_ID), avg(Percent_Complete)from ATT_Table, Employee_Table where ATT_Table.Assigned_To_ID = Employee_Table.Emp_IDgroup by Emp_ID, F_Name

请尝试以下操作:
select Emp_ID, F_Name, count(Act_ID), avg(Percent_Complete)from ATT_Table, Employee_Table where ATT_Table.Assigned_To_ID = Employee_Table.Emp_IDgroup by Emp_ID, F_Name