Mysql 一行之和'；s（两列'；s平均值）和同一行'；s（另一列的值）

我已经写了一个查询，但它显示错误。我想获得

mid_1_english

和

mid_2_english

的平均值，然后想将该平均值与

学期期末英语

相加

select s_roll_no, s_f_name, s_l_name, s_class, 
           SUM(mid_1_english + mid_2_english)/2 as mid_english, 
           SUM(mid_1_mathematics + mid_2_mathematics)/2 as mid_mathematics, 
           SUM(mid_english + semester_final_english) as total_english, 
           SUM(mid_mathematics + semester_final_mathematics) as total_mathematics 
from elaborate_result 
group by s_f_name, s_l_name;
LIMIT 0, 50000 

错误代码：1054。“字段列表”0.000中的未知列“mid_english” 秒

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当你这样做的时候

    Select SUM(mid_1_english + mid_2_english)/2 as mid_english 

    select s_roll_no, s_f_name, s_l_name, s_class, 
       SUM(mid_1_english + mid_2_english)/2 as mid_english, 
       SUM(mid_1_mathematics + mid_2_mathematics)/2 as mid_mathematics, 
       SUM((mid_1_english + mid_2_english)/2 + semester_final_english) as 
     total_english, 
      SUM((mid_1_mathematics + mid_2_mathematics)/2 + 
     semester_final_mathematics) as total_mathematics 
    from elaborate_result 
  group by s_f_name, s_l_name;
 LIMIT 0, 50000 

它不会创建新的mid_english专栏。因此，不能将其用作同一查询中的列

所以你需要的可能是这样的

    Select SUM(mid_1_english + mid_2_english)/2 as mid_english 

    select s_roll_no, s_f_name, s_l_name, s_class, 
       SUM(mid_1_english + mid_2_english)/2 as mid_english, 
       SUM(mid_1_mathematics + mid_2_mathematics)/2 as mid_mathematics, 
       SUM((mid_1_english + mid_2_english)/2 + semester_final_english) as 
     total_english, 
      SUM((mid_1_mathematics + mid_2_mathematics)/2 + 
     semester_final_mathematics) as total_mathematics 
    from elaborate_result 
  group by s_f_name, s_l_name;
 LIMIT 0, 50000 

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使用fiddle链接和整个错误消息更新您的问题编辑您的问题并添加错误消息+更多信息。这不应该出现在评论中检查您的列\u name mid\u english

mid\u english

不是表

detailure\u result

的一列。先解决这个问题，然后回来我正在用mid_英语存储mid_1_英语和mid_2_英语的平均值，如果我解决了这个问题，问题就不会出现了。下次再讨论这个问题。非常感谢，这正是我一直在寻找的答案