zoukankan      html  css  js  c++  java
  • 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
  • 相关阅读:
    Java实现单链表的各种操作
    LintCode #452 删除链表中的元素
    前两天做项目遇到了sqlserver最大连接数 Max Pool Size 的问题
    Redis的应用场景
    说一说MVC的Authentication过滤(四)
    MVC中的下载文件及上传
    Python之高级特性
    说一说MVC的MenuCard(五)
    说一说MVC的CSRF(三)
    说一说MVC的控制器(二)
  • 原文地址:https://www.cnblogs.com/pengp/p/6880040.html
Copyright © 2011-2022 走看看