SELECT EMPS.empid FROM EMPS,PAY,OFFICES,DEPS
   WHERE EMPS.empid = PAY.empid AND PAY.sal < 40000 AND
   EMPS.locid = OFFICES.depid AND OFFICES.name = 'Boston' 
   AND 2 = (SELECT COUNT(*) FROM DEPS WHERE DEPS.parentid
   = EMPS.empid);