zoukankan      html  css  js  c++  java
  • concat()用法

      

    SELECT school_code,`name`,phone from student WHERE login_name REGEXP 'ning$'LIMIT 10;

                

     concat()

    • SELECT CONCAT(school_code,`name`) from student WHERE login_name REGEXP 'ning$' LIMIT 10;

               

    • SELECT CONCAT(school_code,`name`,phone) from student WHERE login_name REGEXP 'ning$' LIMIT 10;(有一个字段是null,concat的结果是null)

              

      CONCAT_WS()

    • SELECT CONCAT_WS('-',school_code,NAME,login_name,phone) from student WHERE login_name REGEXP 'ning$' LIMIT 10;

               

    •  SELECT `name`,MIN(id) FROM student GROUP BY `name` HAVING COUNT(id) >=2 LIMIT 10;

              

     GROUP_CONCAT()

    • SELECT id,`name` from student WHERE `name`='刘媛媛' LIMIT 10;

                

    • SELECT NAME,GROUP_CONCAT(id) from student WHERE `name`='刘媛媛' LIMIT 10;

               

    •  SELECT NAME,GROUP_CONCAT(id) FROM student GROUP BY `name` HAVING COUNT(id) >=2 LIMIT 10;

              

  • 相关阅读:
    从域名锁定该网站所在城市
    微信接口开发 2----接收微信接口返回的数据
    微信接口开发1--向微信发送请求--获取access_token
    MVC-前端设计
    MVC-第一个简单的程序
    MVC-基础02
    MVC-基础01
    表值函数
    视图

  • 原文地址:https://www.cnblogs.com/vanoraxnc/p/8981698.html
Copyright © 2011-2022 走看看