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  • mysql 子查询

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

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  • 原文地址:https://www.cnblogs.com/sea-stream/p/11308830.html
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