A.内连接 B.交叉连接 C.左连接 D.全连接
3.下列SELECT 语句中,哪些子句可以包含子查询? C
A.SELECT B.GROUP BY C.WHERE D.ORDER BY
4.如果使用逗号分隔连接查询两个表,其中一表有20 行,而另一个表有50 行,如果未使
用
WHERE 子句,则将返回多少行? B
A.20 B.1000 C.50 D.500
5.下列的SELECT 语句中哪个不能正常运行? D
A.
SELECT STD,SNAME,SCLASS,CNAME FROM STUDENT S,CLASS C
WHERE SCLASS=CID;
B.
SELECT * FROM STUDENT S,CLASS C WHERE SCLASS=CID;
C.
SELECT S.SID,S.NAME,SCLASS,C.CNAME FROM STUDENT S,CLASS C
WHERE S.SCLASS=C.CID;
D.
SELECT S.SID,S.SNAME,SCLASS,C.CNAME FROM STUDENT
WHERE SCLASS S IN (SELECT CID FROM CLAS C);
6.下面的A SELECT 语句用于查询SCHOOL 模式中的STUDENT 、CLASS 和
DEPARTMENT 表中的信息。完成该语句,使其可以正常运行。
SELECT s.sname,s.saddress,c.cname,D.DNAME,D.DOFFICE
FROM STUDENT S _________ CLASS C ________ _________ DEPARTMENT D
WHERE D.DNAME='法律系';
A.JOIN、ON S.SCLASS=C.CID、JOIN、ON D.DID=C.DEPARTMENT
B.NATURAL JOIN、ON D.DID=C.DEPARTMENT、JOIN、ON S.SCLASS=C.CID
C.CROSS JOIN、ON S.SCLASS=C.CID、JOIN、ON D.DID=C.DERPARTMENT
D.JOIN、ON S.SCLASS=C.CID、NATURAL JOIN、ON D.DID=C.DEPARTMENT
7.在下面各选项中, B 与下面SELECT 语句的查询结果相同。
SELECT SID,SNAME,SADDRESS FROM STUDENT
WHERE SCLASS='C0010545' OR SCLASS IN( SELECT CID FROM CLASS
WHERE DEPARTMENT IN(
SELECT DID FROM DEPARTMENT
WHERE DNAME='化工系'));
A.
SELECT SID,SNAME,SADDRESS FROM STUDENT WHERE SCLASS='C0010545'
INTERSECT
SELECT SID,SNAME,SADDRESS FROM STUDENT S,CLASS C
WHERE S.SCLASS=C.CID AND C.DEPARTMENT IN
(SELECT DID FROM DEPARTMENT WHERE DNAME='化工系');
B.
SELECT SID,SNAME,SADDRESS FROM STUDENT WHERE SCLASS='C0010545'
UNION
SELECT SID,SNAME,SADDRESS FROM STUDENT S,CLASS C
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