使用教学（STC）数据库，与如下查询语句等价的是（ ）。 SELECT *FROM Student WHERE Sdept = 'CS' EXCEPT SELECT * FROM Student WHERE Sage <= 19;
A: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage > 19
B: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage <= 19
C: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage <= 19
D: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage > 19
A: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage > 19
B: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage <= 19
C: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage <= 19
D: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage > 19
举一反三
- 在所有学生中查询比计算机系学生平均年龄大的学生姓名，可以使用的查询语句是： A: SELECT Sname FROM Student WHERE Sage > ( SELECT AVG(Sage) FROM Student ); WHERE Sdept = 'CS' B: SELECT Sname FROM Student WHERE Sage > AVG( SELECT Sage FROM Student WHERE Sdept = 'CS' ); C: SELECT Sname FROM Student WHERE Sage > ( SELECT AVG(Sage) FROM Student WHERE Sdept = 'CS' ); D: SELECT Sname FROM Student WHERE AVG(Sage) > ( SELECT Sage FROM Student WHERE Sdept = 'CS' );
- 对教材79页学生表的查询，若描述条件‘年龄大于计算机系某个学生的年龄’，可以表示为： A: WHERE sage>ANY(SELECT sage FROM student WHERE sdept='CS') B: WHERE sage>SOME(SELECT sage FROM student WHERE sdept='CS') C: WHERE sage>ALL(SELECT sage FROM student WHERE sdept='CS') D: WHERE sage>(SELECT MIN(sage) FROM student WHERE sdept='CS'))
- 在所有学生中查询比计算机系所有学生年龄都要大的学生姓名,正确的查询语句是___________________。 A: SELECT Sname FROM Student WHERE Sage > ( SELECT MAX(Sage) FROM Student WHERE Sdept = 'CS'); B: SELECT Sname FROM Student WHERE Sage > ALL ( SELECT Sage FROM Student WHERE Sdept = 'CS'); C: SELECT Sname FROM Student S1 WHERE EXISTS ( SELECT Sage FROM Student S2 WHERE Sdept = 'CS' AND S1.Sage > S2.Sage); D: SELECT Sname FROM Student S1 WHERE NOT EXISTS ( SELECT * FROM Student S2 WHERE Sdept = 'CS' AND S1.Sage <= S2.Sage);
- 查询所有非计算机系学生的信息，不正确的SQL语句是：（ ） A: SELECT * FROM Student WHERE Sdept != 'CS'; B: SELECT * FROM Student WHERE NOT Sdept = 'CS'; C: SELECT * FROM Student WHERE Sdept IN ('MA', 'IS'); D: SELECT * FROM Student WHERE NOT Sdept IN ('CS');
- 查询语句 SELECT * FROM Student WHERE Sdept =...Sage <= 19; 可以等价为：（