• mysql 获取学生个人科目平均分


    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 | xiaobai  |    80 | english   |
    | 11 | xiaobai  |    80 | physics   |
    | 12 | xiaobai  |    80 | shuxue    |
    | 13 | xiaohei  |    80 | astronaut |
    | 14 | xiaohei  |    80 | shuxue    |
    | 15 | xiaohei  |    80 | physics   |
    | 16 | xiaohei  |    80 | english   |
    +----+----------+-------+-----------+
    16 rows in set (0.00 sec)
    
    
    
    mysql> select name,avg(score) from test group by name;
    +----------+------------+
    | name     | avg(score) |
    +----------+------------+
    | xiaobai  |    80.0000 |
    | xiaohei  |    80.0000 |
    | xiaohong |    82.2500 |
    | xiaoming |    82.2500 |
    +----------+------------+
    4 rows in set (0.01 sec)
    
    
    
    mysql> select name,sum(score)/count(*) from test group by name;
    +----------+---------------------+
    | name     | sum(score)/count(*) |
    +----------+---------------------+
    | xiaobai  |             80.0000 |
    | xiaohei  |             80.0000 |
    | xiaohong |             82.2500 |
    | xiaoming |             82.2500 |
    +----------+---------------------+
    4 rows in set (0.00 sec)

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  • 原文地址:https://www.cnblogs.com/sea-stream/p/11305668.html
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