实验一
(1)无条件单表查询
select sname NAME,'year of birth:' BIRTH,20xx-sage BIRTHDAY,LOWER(sdept) DEPARTMENT FROM student; (2)有条件单表查询
SELECT sname,sdept,sage FROM student WHERE sage NOT BETWEEN 20 AND 23; (3)单表嵌套(一层)查询
SELECT sno,sname,sdept FROM student WHERE sdept IN(SELECT sdept FROM student WHERE sname='刘晨');
(4)复合条件多表查询
SELECT student.sno,sname,cname,grade FROM student ,sc,course WHERE student.sno=sc.sno AND sc.cno=course.cno;
(5)使用COUNT()的单表查询 SELECT COUNT(*) FROM student; (6)使用AVG()的单表查询
SELECT AVG(grade) '平均成绩' from SC where CNO='1'; (7)查询结果分组
SELECT cno,COUNT(sno) '人数' FROM sc GROUP BY cno; (8)查询结果排序
SELECT * FROM student ORDER BY sdept,sage DESC; (9)使用通配符的查询
SELECT sname,sno,ssex FROM student WHERE sname NOT LIKE'刘%';
(10)使用换码字符的单表查询
SELECT cno,ccredit FROM course WHERE cname LIKE 'DB\_Design'ESCAPE'\'; (11)插入单个元组 插入一个新学生元组
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