河南成教 / SQL Server
正确率:100%
现有顾客表customers, 包含数据如下表,若执行sql语句:select count(distinct(city from customers,以下()是输出结果 cid cname city
jac null
2 lee beijing
3 tom
4 chen beijing
A.1
B.2
C.3
D.4
jac null
2 lee beijing
3 tom
4 chen beijing
参考答案: