T-Sql（一）简单语法

　　Sql Server是鄙人学习的第一种数据库，对Sql Server有一种特别的情感，下面就说一下Sql Server的简单语法，适用初学者。

　　1,创建数据库create database

create database My_FrirstCreate           --创建数据库
go

use My_FrirstCreate           --连接数据库 
go

　　2,创建表create table

create table dbo.Students          --创建表（数据类型，是否NULL）
  (StudentID int primary key not null, Name varchar(25)not null, Scores int null) go

　　3,插入数据insert

insert dbo.Students(StudentID,Name,Scores)    --插入数据 
   values(100204201,'张三',50) go

insert dbo.Students values(100204202,'李四',null) go

insert into table1              --利用insert，select向表里插数据 
select ID,Name,Date from table2 where Name="张三"; go

 　　4,使用select，into创建新表

select{列名}       --使用select，into创建新表
into 新表名 from 旧表；

　　5,更新,删除数据update delete

update dbo.Students         --更新数据
   set Scores=70
   where StudentID=100204202
go
delete from Students where Name='张三'

 　　6,改变字段的属性

alter table Produce.Product     --改变字段的属性
alter column Name char(50) not null

　　7,数据类型转换

print cast ('2011-12-12' as datetime)     --cast类型转换
print convert(datetime,getdate())         --convert类型转换

　　8,like查询语法

--检索名称以‘hl’开头的信息
select t.ProductKey,t.ModelName from dbo.DimProduct t where t.ModelName like 'hl%'; --检索名称以‘hl’结尾的信息
select t.ProductKey,t.ModelName from dbo.DimProduct t where t.ModelName like '%hl'; --检索名称类似‘hl’的信息
select t.ProductKey,t.ModelName from dbo.DimProduct t where t.ModelName like '%hl%';

　　9,条件查询语法

--每种颜色有多种件产品：
select COUNT(*) from dbo.DimProduct; select * from dbo.DimProduct where Color = 'black'; select count(*) from dbo.DimProduct where Color = 'black'; --分组：
select color from dbo.DimProduct; select color,COUNT(*) from dbo.DimProduct group by Color; --商品库中：相同颜色产品数量大于50的商品颜色
select color,COUNT(*) from dbo.DimProduct group by Color having count(*) >= 50; select * from dbo.DimProduct order by Color asc; select color,COUNT(*) from dbo.DimProduct group by Color having count(*) >= 50
order by COUNT(*) asc; select color,COUNT(*) from dbo.DimProduct group by Color having count(*) >= 50
order by COUNT(*) desc; --商品库中：1998生产的，相同颜色产品数量大于5的商品颜色
select color,COUNT(*) from dbo.DimProduct where YEAR(StartDate)=1998
group by Color having count(*) >= 50
order by COUNT(*) desc; select color,count(*) from dbo.DimProduct t where YEAR(t.StartDate)>1998
group by color having COUNT(*)>50
order by COUNT(*) desc;

 　　10,联接join语法

select m.LoginID as ManagerLoginID,e.*       --左联接
from HumanResources.Employee e left join HumanResources.Employee m on m.employeeID = e.ManagerID select m.LoginID as ManagerLoginID,e.*       --右联接
from HumanResources.Employee e right join HumanResources.Employee m on m.employeeID = e.ManagerID

 

 　　本文只是简单的介绍下T-Sql语法，复杂的语法将下面的文章讲解...