試題詳解

30)假设”订单”表中有订单号、职员号、客户号和金额字段,正确的SQL语句只能是
(A)SELECT职员号FROM订单 GROUP BY职员号HAVING COUNT(*)>3 AND AVG_金额>200
(B)SELECT职员号FROM订单 GROUP BY职员号HAVING COUNT(*)>3 AND AVG(金额)>200
(C)SELECT职员号FROM订单 GROUP,BY职员号HAVING COUNT(*)>3 WHERE AVG(金额)>200
(D)SELECT职员号FROM订单 GROUP BY职员号WHERE COUNT(*)>3 AND AVG_金额>200