A、 SELECT cust_name FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT cust_name FROM Customers WHERE cust_name = 'Fun4All';
B、 SELECT cust_name FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT cust_contact FROM Customers WHERE cust_name = 'Fun4All';
C、 SELECT * FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT * FROM Customers WHERE cust_name = 'Fun4All';
D、 SELECT * FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT cust_name FROM Customers WHERE cust_name = 'Fun4All';
答案:AC
A、 SELECT cust_name FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT cust_name FROM Customers WHERE cust_name = 'Fun4All';
B、 SELECT cust_name FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT cust_contact FROM Customers WHERE cust_name = 'Fun4All';
C、 SELECT * FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT * FROM Customers WHERE cust_name = 'Fun4All';
D、 SELECT * FROM Customers WHERE cust_state IN ('IL','IN','MI' ) UNION SELECT cust_name FROM Customers WHERE cust_name = 'Fun4All';
答案:AC
A. enddate
B. 3enddate
C. 2020enddate
D. while
A. then
B. for
C. while
D. when
A. SUM
B. AVG
C. MAX
D. MIN
A. if exists
B. exists
C. having
D. if existing
A. select s_id from SC group by s_id where count(*) > C
B. select s_id from SC group by s_id having count(*) > C
C. select s_id from SC where count(*) > C order by s_id
D. select s_id from SC having count(*) > C
A. 数据
B. 模型
C. 账号
D. 代码
A. select语句
B. create语句
C. insert语句
D. drop语句
A. 一般来说,表连 接都可以用子查 询替换
B. 一般来说,子查 询都可以用表连 接替换
C. 相对于表连接, 子查询适合于作 为查询的筛选条 件
D. 相对于表连接, 子查询适合于查 看多表的数据