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  • mysql union 组合查询

    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 id,name from user where name="xiaohong" union select id,name from test where name="xiaoming";
    +------+----------+
    | id   | name     |
    +------+----------+
    |    3 | xiaohong |
    |    1 | xiaoming |
    |    6 | xiaoming |
    |    7 | xiaoming |
    |    8 | xiaoming |
    +------+----------+
    5 rows in set (0.00 sec)
    
    
    
    mysql> select id,name from user where name="xiaohong" union all select id,name from test where name="xiaoming";
    +------+----------+
    | id   | name     |
    +------+----------+
    |    3 | xiaohong |
    |    1 | xiaoming |
    |    6 | xiaoming |
    |    7 | xiaoming |
    |    8 | xiaoming |
    +------+----------+
    5 rows in set (0.00 sec)
    
    
    
    mysql> select id,name from user where name="xiaohong" union all select id,name from test where name="xiaoming" order by id;
    +------+----------+
    | id   | name     |
    +------+----------+
    |    1 | xiaoming |
    |    3 | xiaohong |
    |    6 | xiaoming |
    |    7 | xiaoming |
    |    8 | xiaoming |
    +------+----------+
    5 rows in set (0.00 sec)

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  • 原文地址:https://www.cnblogs.com/sea-stream/p/11312829.html
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