SQL Server 常用關鍵字

 

SQL 建庫 建表

 

--1.創建一個數據庫
create database School;
--刪除數據庫
drop database School;
--創建數據庫的時候指定一些選項。
create database School
on primary
(
    name='School',
    filename='C:\Program Files\SQL\MSSQL12.MSSQL\MSSQL\DATA\School.mdf',
    size=5MB,
    --filegrowth=10MB,
    filegrowth=10%,--按照文件的百分比來增長
    maxsize=100MB
)
log on
(
    name='School_log',
    filename='C:\Program Files\SQL\MSSQL12.MSSQL\MSSQL\DATA\School.ldf',
    size=3MB,
    filegrowth=3%,
    maxsize=20MB
)

--切換數據庫
use School;

 

TOP 

select top 10 * from student            查詢前十條

select top 10 percent * from student    查詢前10%；

Distinct

select distinct * from student   查詢不重復

Avg Count Sum Min MAx

select AVG(ID) from student   平均數
select COUNT(ID) from student 總數
select Sum(ID) from student   求和
select Max(ID) from student   求最大數
select Min(ID) from student   求最小

Where And Or

select * from student where ID>90 and ID<100 and ID%2=0

select * from student where ID>100 or ID<10 and ID%2!=0

模糊查詢 Like   Not Like % _

select * from student where Name  like '%三%'        查詢帶有三的
select * from student where Name  not like '%三%'    查詢不帶有三的
select * from student where Name  like '三%'         查詢三開頭的
select * from student where Name  like '%三'         查詢三結尾的
select * from student where Name  like '_ 三 %'      查詢第二個為三的

 Order By   where  desc asc 排序

select * from NT_User order by UserAge  按年齡大小排序

select * from NT_User order by UserAge asc  降序

select * from NT_User order by UserAge desc  升序

Group By  Having 分組 （要和聚合函數一起使用）

select UserGender from NT_User group by UserGender  按性別分成三組

select UserGender, Count(*)  from NT_User group by UserGender 查詢三組性別的每個的個數

select UserGender,COUNT(*) from NT_User group by UserGender having COUNT(*) >1000  查詢三組性別的每個的個數大於1000的

 Union  Union All

select Name from Student union all select Name from Teacher  兩表聯查 所有的

select Name from Student union select Name from Teacher      兩表聯查 去除重復的

Select Into  Insert Into

select * into teacher from Student          創建Teacher表 並把Student表里面的數據復制到Teacher表中

insert into teacher select * from Student   把Student表里面的數據復制到Teacher表中

 Inner Join on 兩表聯查

select A.Content,B.UserName from CLN_Resource as A inner join NT_User as B on A.UserID =B.UserID

select * from CLN_Resource inner join NT_User on CLN_Resource.UserID=NT_User.UserID