Question: Among all the employees who don't wish to receive promotion e-mails, how many of them belong to or once belonged to the Engineering Department?
SQL: SELECT COUNT(T1.BusinessEntityID) FROM EmployeeDepartmentHistory AS T1 INNER JOIN Person AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID INNER JOIN Department AS T3 ON T1.DepartmentID = T3.DepartmentID WHERE T3.Name = 'Engineering' AND T2.EmailPromotion = 0