SQL Server数据库常用语句总结大全

--创建库
create database Demo01;

create database 数据库名
on primary
(
         name='逻辑名称',
        filename='文件存储路径',
)
log on
(
        name='逻辑名称',
        filename='文件存储路径',
)

--创建数据库（自定义初始值）
create database Demo02
on primary
(
    name='Demo02',
    filename='M:\SQLServer_File\Demo02_Data\Demo02.mdf',
    size=5MB
)
log on
(
    name='Demo02_Log',
    filename='M:\SQLServer_File\Demo02_Data\Demo02_Log.ldf',
    size=2MB
)

--创建数据库（自定义初始值）
create database Demo03
on primary
(
	name='Demo03',
	filename='M:\SQLServer_File\Demo03_Data\Demo03_Data.mdf',
	size=5MB
)
log on
(
	name='Demo02_Log',
	filename='M:\SQLServer_File\Demo03_Data\Demo03_Log.ldf',
	size=2MB
)

--删库语句
drop database Demo03

use Demo01
GO
create table student
(
	Sno char(5) NOT NULL UNIQUE,  -- UNIQUE 唯一值
	Sname char(8) NOT NULL,
	Sage smallint default 20,  --default 默认值
	Sex char(2) check(Sex='男' or Sex='女')
)

-- 创建视图
USE Demo01
GO
CREATE VIEW Demo01_View_student
as
	select * from student
GO

-- 主键约束
use Demo02
GO
create table student1
(
	Sno char(5) primary key
)

use Demo02
GO
create table student2
(
	Sno char(5),
	Sname char(5),
	constraint c1 PRIMARY KEY(Sno)
)

use Demo02
GO
create table student3
(
	Sno char(5),
	constraint c2 primary key(Sno)
)
GO
create table student4
(
	Sno char(5),
	Cno char(5),
	constraint c3 primary key(Cno),
	constraint c4 foreign key(Sno) references student3(Sno)

)

-- 非空约束
use Demo02
GO
create table student5
(
	Sno char(5) not null
)

-- 唯一约束
use Demo02
go
create table student6
(
	Sno char(5) unique
)

insert into student(Sno, Sname) values ('s0001', '张三');

delete from student where Sno='s0001' 
delete from student where Sno='s0001' and Sage not in (20,21)

use Demo02
go
alter table student drop constraint CK__student__Sex__108B795B

update student set Sno='s001',Sname='李四',Sage=25,Sex='女' where Sname='张三'

select * from student

select Sno,Sname from student where Sage=20

select Sno as 学号 from student
select Sno 学号 from student

select Sno 学号,Sname 姓名,Sage*0.5 年龄 from student where Sage=20;
select Sno 学号,Sname 姓名,Sage+100 年龄 from student where Sage=20;
select Sno 学号,Sname 姓名,Sage/4 年龄 from student where Sage=20;

select Sno,Sname,Sage,Sex from student order by Sage asc

select Sno,Sname,Sage,Sex from student order by Sage desc

select Sno,Sname,Sage,Sex from student order by Sage desc, Sno asc
select Sno,Sname,Sage,Sex from student order by Sage desc, Sno desc

select Sno,Sname,Sage,Sex from student order by 1 desc
select Sno,Sname,Sage,Sex from student order by 3 asc

-- 学生表年龄不重复
select distinct Sage from student
-- 学生表姓名和年龄不重复
select distinct Sname,Sage from student

select * into TU_student from student where Sex='男'

insert into TU_student(Sno,Sname,Sage,Sex)
select * from student where Sex='女'

-- 跨数据库插入
insert into Demo02.dbo.student(Sno,Sname,Sage,Sex)
select * from Demo01.dbo.student

select count(*) from student

--  性别为男的行数
select count(*) from student where Sex='男'

select max(Sage) 最大值, min(Sage) 最小值 from student

select TU_student.Sex,MAX(student.Sage) 最大年龄,MIN(student.Sage) 最小年龄 
	from TU_student,student 
		where TU_student.Sno=student.Sno 
			group by TU_student.Sex

select TU_student.Sname,MAX(student.Sage) 最大年龄,MIN(student.Sage) 最小年龄 
	from TU_student,student 
		where TU_student.Sno=student.Sno 
			group by TU_student.Sname

select AVG(Sage) from student

select Sex 性别,AVG(Sage) 平均年龄 from student group by Sex

select TU_student.Sno,student.Sname,TU_student.Sage,student.Sex 
	from TU_student,student 
		where TU_student.Sno = student.Sno

select TU_student.Sno,student.Sname,TU_student.Sage,student.Sex 
	from student join TU_student on student.Sno = TU_student.Sno

select * from student where Sno like '0%'

select * from student where Sname like '%三'

select * from student where Sno like '%0%'

select * from student where Sno like '00_'

select * from student where Sno like 's___'

--  男女分别多少人
select Sex, count(*) 人数 from student group by Sex

-- 学号是否为001
select Sno 学号,case  when Sno='001' then 'true' else 'false' end 是否为001 from student


-- 性别是否为男
select Sno 学号,Sname 姓名,Sage 年龄, Sex 性别,
	case  when Sex='男' then 'true' else 'false' end 性别是否为男 from student

SELECT DATEDIFF(day,'2024-03-01','2024-04-01') AS 日期差多少天

SELECT DATEDIFF(day,day1,day2) AS 日期差多少天 from a_dateTable

-- 吧001学号转为int数据类型
select CAST(Sno as int) from student where Sno='001'
-- 吧年龄转为char数据类型
select CAST(Sage as char) from student

alter database Demo02 set offline with rollback immediate

exec sp_detach_db @dbname=N'Demo02'

exec sp_attach_db @dbname=N'Demo02', 
	@filename1=N'M:\SQLServer_File\Demo02_Data\Demo02.mdf',
	@filename2=N'M:\SQLServer_File\Demo02_Data\Demo02_Log.ldf'