T-Sql(一)简单语法

原文: 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...

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