最基础最简单SQL语句.doc

/*create table s ( sn char(20) , sno char(8) , sex char(2) check(sex=男or sex=女), age int check (age=18 and age=25) ) create table c ( sno char(20) primary key, cn char(20) unique, cno char(10) not null, score int check (score=0 and score=100) ) alter table s add dept char(20) alter table s add sno char primary key ? select sn,sno from s select * from s select sn, 2010-age from s select sn as 姓名, 2010-age as 出生年份 from s select distinct dept from s select sno,score from c where cno=1002 select sno,cno,score from c where score=85 select sno,cno,score from c where score85 select sn,dept,age from s where age=19 and age=23 select sn,dept,age from s where between19 and 23 ? select sn,dept, age from s where age18 or age23 select sn,sex from s where dept in(a,b) select sn,sex from s where dept=a or dept=b select * from s where sn like张% select * from s where sn like_四 create table sc ( sno char(8), cno char(10), sn char(20), cn char(20), score int ) select sno,cno,cn,score from c where (cno=1001 or cno=1002) and score=80 select cno as 学号, count(sno) as 选课人数 from c group by cno select sno,cn,cno from c where (cno=1001 or cno=1002) and score=80 order by cno desc select * from c order by sno, score desc ？ select top 5 score from c order by score desc select * from c order by sn, score desc */