Show the name and number of employees for the departments managed by heads whose temporary acting value is 'Yes'?
SELECT T1.name ,  T1.num_employees FROM department AS T1 JOIN management AS T2 ON T1.department_id  =  T2.department_id WHERE T2.temporary_acting  =  'Yes'
departments managed by heads refers to JOIN on department and management tables; whose temporary acting value is 'Yes' refers to T2.temporary_acting = 'Yes'; name and number of employees refers to T1.name, T1.num_employees;