数据库练习

插入 几条老师信息 和成绩、用SQL插入几条员工信息（注意：bit类型，在写代码中用1或0来表示，不要用’false’,会进行类型转换的。）

create table TblTeacher

(

tTId int identity(1,1) primary key,

tTName nvarchar(50) not null,

tTGender bit default(1),

tTAge int,

tTSalary money,

tTBirthday datetime

)

insert into TblTeacher

select '商炳奇',1,22,10000,'1991-10-30' union

select '刘祎',0,22,10000,'1991-11-06' union

select '耿宇丹',0,21,10000,'1992-12-30' union

select '张少丹',0,22,10000,'1991-6-6' union

select '王静静',0,22,10000,'1991-6-6' union

select '段琳琳',0,22,10000,'1991-6-6' union

select '杨巧巧',0,21,10000,'1991-6-6'

create table TblStudent

(

studentId int identity(1,1) primary key,

tScoreId int not null,

sName nvarchar(50) not null,

sAge int not null,

sNo numeric(18,0),--身份证号，十八位数字，小数位0

sEmail varchar(50),

sGender bit default(1),

sBirthday datetime

)

insert into TblStudent

select 1,'刘备',20,123456789012345678,'123@163.com',1,'1987-5-6' union

select 1,'关羽',19,123456789012345671,'1sfdsf3@163.com',1,'1988-8-6' union

select 1,'张飞',18,123456789012345672,'12sfsd3@163.com',1,'1989-5-19' union

select 4,'曹操',22,123456789012345673,'12sf3@163.com',1,'1985-12-6' union

select 4,'夏侯惇',22,123456789012345674,'1ff23@163.com',1,'1985-3-6' union

select 4,'华佗',50,12345678901234565,'12ff3@163.com',1,'1957-1-16' union

select 4,'甄姬',18,12345678901234565,'12f3@163.com',0,'1989-8-8'

create table TblScore

(

tScoreId int identity(1,1) primary key,

studentId int not null, --学生id，外键

tEnglish float,

tMath float

)

insert into TblScore

select 1,90,97 union

select 2,90,70 union

select 3,59,100 union

select 4,100,80 union

select 5,60,96 union

select 6,0,100 union

select 7,80,60

练习1：给studentId是1的英语成绩加10分

update TblScore set tEnglish=tEnglish+10 where studentId=1

练习2：考试题偏难，所有人的成绩加5分

update TblScore

set tEnglish=

(

case when tEnglish+5<=100 then tEnglish+5

when tEnglish+5>=100 then 100

end

),

tMath=

(

case when tMath+5<=100 then tMath+5

when tmath+5>=100 then 100

end

)

练习3：所有女学生的年龄减1岁

update TblStudent set sAge=sAge-1 where sGender=0

删除工资大于2000的老师

delete from TblTeacher where tTSalary>2000

============将老师表清空========

删除所有老师

delete from TblTeacher

删除数据时候 把自增长列的值还原成种子

truncate table TblTeacher