SQL Server数据库常用语句总结大全

目录

• 1. 建库语句
• 2. 删库语句
• 3. 创建数据表
• 4. 创建视图
• 5. 约束语句
• 5.1 主键约束（PRIMARY KEY）
• 5.2 外键约束（FOREIGN KEY）
• 5.3 非空约束（NOT NULL）
• 5.4 唯一约束（UNIQUE）
• 6. 增加语句（insert）
• 7. 删除语句（delete）
• 7.1 删除表数据（一行）
• 7.2 删除约束
• 8. 修改语句（update)
• 9. 查询语句（select）
• 9.1 查询全部
• 9.2 查询某列
• 9.3 自定义查询
• 9.3.1 列名的重命名
• 9.3.2 列名的加减乘除
• 9.4 正倒序排列
• 9.4.1 升序
• 9.4.2 降序
• 9.4.3 升序和降序同时存在
• 9.4.4 选择某列排序
• 9.5 去除重复项
• 9.6 把一个表的数据插入另一个表
• 9.7 求总行数
• 9.8 求最大值和最小值
• 9.9 求平均值
• 9.10 连接查询
• 9.10.1 第一种连接方式
• 9.10.2 第二种连接方式
• 9.11 模糊查询（LIKE）
• 9.11.1 以特定字符开头的字符串
• 9.11.2 以特定字符结尾的字符串
• 9.11.3 匹配包含特定字符的字符串
• 9.11.4 使用 _ 匹配单个字符
• 9.11.5 使用多个 _ 匹配多个单个字符
• 9.12 分组查询（GROUP BY）
• 10. 常用函数
• 10.1 判断语句（CASE WHEN）
• 10.2 日期差（DATEDIFF）
• 10.3 数据类型转换（CAST）
• 11. 断开数据库
• 12. 分离数据库
• 13. 附加数据库
• 总结 

--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 (null,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'