SQL语句练习二
use LIANXI Create table student--学生表 ( ssno varchar(50) not null primary key,--主键学生学号 ssname varchar(50) not null,--学生姓名 sssex varchar(50) not null,--学生性别 sbirthday date,--学生出生年月 ssclass varchar(50) not null,--学生班级 ) --primary key identity(1,1)自增长加入后设置的列无需输入也可自动成序号并排序,此列若需手动输入,就不 insert into student values('108','曾华','男','1977-09-01','95033') insert into student values('105','匡明','男','1975-10-02','95031') insert into student values('107','王丽','女','1976-01-23','95033')--学生信息 insert into student values('101','李军','男','1977-02-20','95033') insert into student values('109','王芳','女','1975-02-10','95031') insert into student values('103','陆君','男','1974-06-03','95031') create table teacher--教师表 (能用自增长 jsno varchar(50) not null primary key,--主键 教师工号 jsname varchar(50) not null ,--教师名字 jssex varchar(50) not null,--教师性别 tbirthday date,--教师出生年月 jsprof varchar(50) not null,--教师职称 jsdepart varchar(50) not null,--教师所在部门 ) insert into teacher values('804','李诚','男','1958-12-02','副教授','计算机系') insert into teacher values('856','张旭','男','1969-03-12','讲师','电子工程系') insert into teacher values('825','王萍','女','1972-05-05','助教','计算机系')--教师信息 insert into teacher values('831','刘冰','女','1977-08-14','助教','电子工程系') create table course --课程表 ( kcno varchar(50) not null primary key,--课程号 主键 kcname varchar(50) not null,--课程名称 jsno varchar(50) references teacher(jsno) not null,--教师工号 ) insert into course values('3-105','计算机导论','825') insert into course values('3-245','操作系统','804') insert into course values('6-166','数字电路','856')--输入课程 insert into course values('9-888','高等数学','831') create table score --成绩表 ( ssno varchar(50) references student(ssno) not null,--学生学号外键 kcno varchar(50) references course(kcno) not null,--课程外键 degree int not null,--课程成绩 ) insert into score values('103','3-245',86) insert into score values('105','3-245',75) insert into score values('109','3-245',68)--输入成绩 insert into score values('103','3-105',92) insert into score values('105','3-105',88) insert into score values('109','3-105',76) insert into score values('101','3-105',64) insert into score values('107','3-105',91) insert into score values('108','3-105',78) insert into score values('101','6-166',85) insert into score values('107','6-166',79) insert into score values('108','6-166',81) --22 --查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。 select ssno,ssname,sbirthday from student where YEAR(sbirthday)=(select YEAR(sbirthday)from student where ssno='108') --YEAR(sbirthday)提取年 --month()提取月 --day()提取天 --dayofyear print datediff(day,'1994-3-12','2015-4-23')--计算两个日期之间的天数 datediff,datepart返回一个int数值 print datename(weekday,'2015-4-23')--计算今天值周几,datename返回一个字符串 print getdate()--获取当前系统时间 --23、查询“张旭“教师任课的学生成绩 select *from score where kcno in (select kcno from course where jsno in (select jsno from teacher where jsname='张旭')) --24、查询选修某课程的同学人数多于5人的教师姓名。 select jsname from teacher where jsno in (select jsno from course where kcno in (select kcno from score group by kcno having COUNT(*)>5)) --25、查询95033班和95031班全体学生的记录。 select *from student where ssclass in('95033','95031') 26、 查询存在有85分以上成绩的课程Cno. select kcno from score where degree>85 27、查询出“计算机系“教师所教课程的成绩表。 select * from score select * from teacher select * from course select * from score where kcno in( select kcno from course where jsno in( select jsno from teacher where jsdepart='计算机系')) 28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。 select jsname,jsprof from teacher where jsprof not in (select jsprof from teacher group by jsprof having count(*)>1) select jsname,jsprof from teacher where jsprof not in (select jsprof from teacher group by jsprof having count(*)>1) select jsname,jsprof from teacher where jsprof not in(select jsprof from teacher where jsprof in (select jsprof from teacher where jsdepart='计算机系') and jsdepart='电子工程系')and jsdepart in('计算机系','电子工程系') 29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。 select * from score where kcno='3-105' and degree>(select min (degree) from score where kcno='3-245') order by degree desc select * from score where kcno='3-105' and degree>any(select degree from score where kcno='3-245') --any前面必须跟比较值 any比较任何一个数 也就是3-245中所有的数 包括最小的数 30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree. select * from score where kcno='3-105' and degree>(select max(degree) from score where kcno='3-245') 31、 查询所有教师和同学的name、sex和birthday. select ssname,sssex,sbirthday from student union select jsname,jssex,tbirthday from teacher 32、查询所有“女”教师和“女”同学的name、sex和birthday. select ssname,sssex,sbirthday from student where sssex='女' union select jsname,jssex,tbirthday from teacher where jssex='女' --union 纵向连接 与 join on 横向连接 不同 两个标的数据类型必须一致不然连不到一起去 --列数也要对应 33、 查询成绩比该课程平均成绩低的同学的成绩表。 select * from score a where degree <(select avg(degree)from score b where a.kcno=b.kcno) 34、 查询所有任课教师的Tname和Depart. select * from course select *from score select *from teacher select jsname,jsdepart from teacher where jsno in(select jsno from course where kcno in(select kcno from score)) 35 、 查询所有未讲课的教师的Tname和Depart. select jsname,jsdepart from teacher where jsno not in(select jsno from course where kcno in(select kcno from score)) 36、查询至少有2名男生的班号。 select *from student select ssclass from student where sssex='男' group by ssclass having COUNT(*)>=2 37、查询Student表中不姓“王”的同学记录。 select *from student where ssname not like '王%' 38、查询Student表中每个学生的姓名和年龄。 select ssname,YEAR(GETDATE())-YEAR(sbirthday) as 年龄 from student 39、查询Student表中最大和最小的Sbirthday日期值。 select MAX(sbirthday),MIN(sbirthday) from student 40、以班号和年龄从大到小的顺序查询Student表中的全部记录。 select *from student order by ssclass desc,sbirthday asc --41查询“男”教师及其所上的课程 select kcname from course where jsno in(select jsno from teacher where jssex='男') 42、查询最高分同学的Sno、Cno和Degree列。 select ssno,kcno,DEGREE from score where degree IN(select max(degree) from score) 43、查询和“李军”同性别的所有同学的Sname. select ssname from student where sssex in(select sssex from student where ssname='李军') 44、查询和“李军”同性别并同班的同学Sname. select ssname from student where sssex in(select sssex from student where ssname='李军') and ssclass in (select ssclass from student where ssname='李军') 45、查询所有选修“计算机导论”课程的“男”同学的成绩表。 select * from score where ssno in (select ssno from student where sssex='男') and kcno in (select kcno from course where kcname='计算机导论') select LEFT('abcdef',2)--从左到右截取固定长度 select RIGHT('abcdef',2)--从右往左截取固定长度 select LOWER('ABC')--转换为小写 select UPPER('abc')--转换为大写 select LEN('qweqwe')--返回一个字符串 长度(int值) print LTRIM(' adasj dajk ')--LTRIM去除字符串左边的空格 print RTRIM(' adasj dajk ')--RTRIM去除字符串右边的空格 print substring('daskdjaskdjwioado',6,2)--从起始位置开始截取固定长度 从6 开始 6为1 所以第二个数是 a print replace('ssdadasrwfa','ss','jk')--第一个是字符串 第二个是被替换的目标 第三个是要替换成的字符串 print replicate('sd',10)--复制 把 sd 复制10遍 print str(123.456,2,2) --存储过程 --定义变量 declare @bianliang int set @bianliang=12--变量赋值 select @bianliang--结果框查看 print @bianliang--消息框查看 -----------------定义两个变量求和 declare @bianliang1 int,@bianliang2 int set @bianliang1=1 set @bianliang2=2 select @bianliang1+@bianliang2 ---创建存储过程 create proc chaxun as--as...go中间写存储过程 select *from student go --存储过程创建后,会存储到对应数据库的可编程性》存储过程文件夹下 exec chaxun--执行存储过程 --带返回值的存储过程 create proc returncount as declare @a int select @a=COUNT(*) from student--查询结果赋值给了变量@a return @a--存储过程返回值 go declare @jieshou int--定义一个变量接受存储过程返回值 exec @jieshou=returncount--正在执行存储过程时,用接受变量去接受返回值 print @jieshou--输出接受结果 -----------带输入参数的存储过程 create proc Jiafa @a int,--输入参数,(用逗号隔开,放在as和存储过程名之间) @b int--输入参数 as return @a+@b go declare @a int exec @a=Jiafa 1,7 --调用带参数的存储过程,需要在存储过程名后输入参数,空格隔开,参数之间“,”隔开 print @a ------输入一个0--100之间的数,判断是一位数还是两位数,返回数字1,2 不在范围内返回 -1 create proc pandingshuzi--创建存储过程 @a int--存储过程的输入参数 as if @a>0 and @a<10 begin return 1 end else if @a>=10 and @a<100 begin return 2 end else begin return -1 end go declare @a2 int--在过程外定义一个接受变量a 用来接受 存储过程 exec @a2=pandingshuzi 999--@a2 print @a