sql server2008r2 添加、修改、删除、查询

1.插入数据行

insert [into] 表名 [(列名)] values（值列表）

例：在对应的数据库school中新建查询，insert into+表名students（列名）+values+(值列表)

insert into students(name,address,grade,emaill,sex)
values('张青ming',DEFAULT,1,'zhang@163',1)

2.通过 insert select 语句将现有表中的数据添加到已存在的表中去

insert into <表名>(列名) select <列名> from <源表名>

例：

insert into new_table(uname,uaddress)
select name,address
from students

3.通过select into 语句将现有表中的数据添加到新表中（适用于备份表，只可用一次）

select <列名> into(表名) from <源表名>

例：

select name,address,grade,emaill,sex
into student_bak
from students

4.通过 union 关键字合并数据进行插入

insert into <列名>(表名)

select <列名> union

select <列名> union

select <列名> union

......

例：

insert into students(name,address,grade,emaill,sex)
select '大宝','湖北',1,null,1 union
select '二宝','湖北',1,null,1 union
select '三宝','湖北',1,null,1

5.使用 update 更新数据行

update <表名> set 列名 = 更新值,列名 = 更新值....[where 更新条件]

例：

update students set name = '张清山' where name = '张青ming'

update students set grade = grade + 90 where grade <=90

update students set name = 'zhangwen',address = '湖北chacha' where code = 3

6.使用 delete 删除数据行

delete [from] <表名> [where<删除条件>]

例：

delete from students where address = ''

7.使用truncate 删除数据行

truncate table 表名

例：truncate table students 

相当于：delete from students 

8.查询语法

select <列名> from <表名> [where <查询条件>] [order by <排序的列名>[asc或desc]]

例：

select code,name,address from students where sex =1 order by code 
select * from students where sex =1 order by code 
select * from students order by code 
select * from students 

9.使用as命名列

例：

select code as '编号',name as '姓名',address as '地址' from students
select  '编号'= code,'姓名' = name,'地址' = address from students
select grade + 5 as '成绩加5显示'from students

 

10.限制行数

限制固定行数

例：

select top 5 * from students
select top 5 name,address from students
select top 5 name,address from students where sex = 1

按百分比返回

select top 20 percent * from students 
select top 20 percent name,address from students
select top 20 percent name,address from students where sex = 1

 11.排序

升序排序

select * from students order by grade  
select * from students order by grade asc

降序

select * from students order by grade desc

多列排序

select * from students order by grade,code 
select * from students order by grade desc,code desc