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  • 【MYSQL】select from group by

    • group by
    mysql> select * from t_user group by lvl;
    +-----+-------+----------+------+--------+
    | uid | uname | tel      | lvl  | salart |
    +-----+-------+----------+------+--------+
    |   1 | alex  | 23131231 | A    |   1100 |
    |   3 | kit   | 87416574 | B    |   1200 |
    |   4 | poker | 41874521 | C    |   1560 |
    +-----+-------+----------+------+--------+
    mysql> select lvl from t_user group by lvl;
    +------+
    | lvl  |
    +------+
    | A    |
    | B    |
    | C    |
    +------+
    • group by + group_concat()
    mysql> select lvl,group_concat(salart) from t_user group by lvl;
    +------+----------------------+
    | lvl  | group_concat(salart) |
    +------+----------------------+
    | A    | 1100,4300            |
    | B    | 1200                 |
    | C    | 1560                 |
    +------+----------------------+
    3 rows in set (0.00 sec)
    
    mysql> select lvl,group_concat(uid) as salary from t_user group by lvl;
    +------+--------+
    | lvl  | salary |
    +------+--------+
    | A    | 1,2    |
    | B    | 3      |
    | C    | 4      |
    +------+--------+
    3 rows in set (0.00 sec)
    
    mysql> select lvl,group_concat(salart) from t_user group by lvl;
    +------+----------------------+
    | lvl  | group_concat(salart) |
    +------+----------------------+
    | A    | 1100,4300            |
    | B    | 1200                 |
    | C    | 1560                 |
    +------+----------------------+
    3 rows in set (0.00 sec)
    
    mysql> select lvl,group_concat(salart) as salary from t_user group by lvl;
    +------+-----------+
    | lvl  | salary    |
    +------+-----------+
    | A    | 1100,4300 |
    | B    | 1200      |
    | C    | 1560      |
    +------+-----------+
    3 rows in set (0.00 sec)
    • #group by + 集合函数
    mysql> select lvl,group_concat(uid) as salary from t_user group by lvl;
    +------+--------+
    | lvl  | salary |
    +------+--------+
    | A    | 1,2    |
    | B    | 3      |
    | C    | 4      |
    +------+--------+
    3 rows in set (0.00 sec)
    
    mysql> select lvl,count(uid) as salary from t_user group by lvl;
    +------+--------+
    | lvl  | salary |
    +------+--------+
    | A    |      2 |
    | B    |      1 |
    | C    |      1 |
    +------+--------+
    3 rows in set (0.00 sec)
    • #group by + having
    mysql> select lvl,group_concat(salart) from t_user group by lvl having group_concat(salart)=1200;
    +------+----------------------+
    | lvl  | group_concat(salart) |
    +------+----------------------+
    | B    | 1200                 |
    +------+----------------------+
    1 row in set (0.00 sec)
    
    mysql> select lvl,group_concat(salart) from t_user group by lvl having group_concat(salart)=1100;
    +------+----------------------+
    | lvl  | group_concat(salart) |
    +------+----------------------+
    | A    | 1100,4300            |
    +------+----------------------+
    1 row in set (0.00 sec)
    
    mysql> 
    mysql> select lvl,count(uid) as salary from t_user group by lvl;
    +------+--------+
    | lvl  | salary |
    +------+--------+
    | A    |      2 |
    | B    |      1 |
    | C    |      1 |
    +------+--------+
    3 rows in set (0.00 sec)
    
    mysql> select lvl,count(uid) as salary from t_user group by lvl having count(uid)>1;
    +------+--------+
    | lvl  | salary |
    +------+--------+
    | A    |      2 |
    +------+--------+
    1 row in set (0.00 sec)
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  • 原文地址:https://www.cnblogs.com/AlexBai326/p/6048918.html
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