zoukankan      html  css  js  c++  java
  • mysql 表联结,内部联结

    mysql> select * from user;
    +------+----------+-----------+
    | id   | name     | address   |
    +------+----------+-----------+
    |    1 | xiaoming | beijing   |
    |    2 | xiaobai  | shandong  |
    |    3 | xiaohong | suzhou    |
    |    4 | xiaohei  | changchun |
    +------+----------+-----------+
    4 rows in set (0.00 sec)
    
    
    
    mysql> select * from test;
    +----+------------+-------+-----------+
    | id | name       | score | subject   |
    +----+------------+-------+-----------+
    |  1 | xiaoming   |    89 | shuxue    |
    |  2 | xiaohong   |    89 | shuxue    |
    |  3 | xiaohong   |    80 | english   |
    |  4 | xiaohong   |    80 | physics   |
    |  5 | xiaohong   |    80 | astronaut |
    |  6 | xiaoming   |    80 | physics   |
    |  7 | xiaoming   |    80 | astronaut |
    |  8 | xiaoming   |    80 | english   |
    |  9 | xiaobai    |    80 | astronaut |
    | 10 | 1.2xiaobai |    80 | english   |
    | 11 | 2.2xiaobai |    80 | physics   |
    | 12 | 3xiaobai   |    80 | shuxue    |
    | 13 | 123xiaohei |    80 | astronaut |
    | 14 | xiaohei    |    80 | shuxue    |
    | 15 | xiaohei    |    80 | physics   |
    | 16 | .12xiaohei |    80 | english   |
    +----+------------+-------+-----------+
    16 rows in set (0.00 sec)
    
    
    
    mysql> select * from user inner join test on test.subject="shuxue" and user.name=test.name;
    +------+----------+-----------+----+----------+-------+---------+
    | id   | name     | address   | id | name     | score | subject |
    +------+----------+-----------+----+----------+-------+---------+
    |    1 | xiaoming | beijing   |  1 | xiaoming |    89 | shuxue  |
    |    3 | xiaohong | suzhou    |  2 | xiaohong |    89 | shuxue  |
    |    4 | xiaohei  | changchun | 14 | xiaohei  |    80 | shuxue  |
    +------+----------+-----------+----+----------+-------+---------+
    3 rows in set (0.00 sec)
    
    
    
    mysql> select * from user,test where test.name=user.name and test.subject="shuxue";
    +------+----------+-----------+----+----------+-------+---------+
    | id   | name     | address   | id | name     | score | subject |
    +------+----------+-----------+----+----------+-------+---------+
    |    1 | xiaoming | beijing   |  1 | xiaoming |    89 | shuxue  |
    |    3 | xiaohong | suzhou    |  2 | xiaohong |    89 | shuxue  |
    |    4 | xiaohei  | changchun | 14 | xiaohei  |    80 | shuxue  |
    +------+----------+-----------+----+----------+-------+---------+
    3 rows in set (0.00 sec)
    
    
    
    mysql> select * from user,test where test.subject="shuxue" and test.name=user.name;
    +------+----------+-----------+----+----------+-------+---------+
    | id   | name     | address   | id | name     | score | subject |
    +------+----------+-----------+----+----------+-------+---------+
    |    1 | xiaoming | beijing   |  1 | xiaoming |    89 | shuxue  |
    |    3 | xiaohong | suzhou    |  2 | xiaohong |    89 | shuxue  |
    |    4 | xiaohei  | changchun | 14 | xiaohei  |    80 | shuxue  |
    +------+----------+-----------+----+----------+-------+---------+
    3 rows in set (0.00 sec)

  • 相关阅读:
    一个开源库:720全景显示
    如何查看mac系统是32位还是64位的操作系统
    iOS ASIHTTPRequest 使用指南
    iOS block里的self
    苹果公司给出的检测 advertisingIdentifier 的方法
    App Store idfa被拒检查办法
    iOS苹果开发者客服电话地址
    iOS项目的目录结构和开发流程(Cocoa China)
    CFBundleVersion与CFBundleShortVersionString
    In App Purchase Statuses
  • 原文地址:https://www.cnblogs.com/sea-stream/p/11312591.html
Copyright © 2011-2022 走看看