返回 SQL 中一列的平均值

Question

我是新手，所以请原谅我说了一些愚蠢的话。假设我有以下 table:

Subject | Test | Mark
His     | E1   | 30
His     | E1   | 36
His     | E2   | 22
His     | E2   | 51
Sci     | E1   | 35
Sci     | E1   | 33
Math    | E1   | 29
Math    | E1   | 52

我想知道如何让 SQL 找到每次考试的平均值，然后像这样显示它：

Subject | Test | Mark
His     | E1   | 33
His     | E2   | 36.5
Sci     | E1   | 34
Math    | E1   | 40.5

Answer 1

Turophile 是正确的。如果需要写出来：

SELECT Subject, Test, AVERAGE(Mark) as Mark FROM tablename GROUP BY Subject, Test

返回 SQL 中一列的平均值

Returning the average of a column in SQL

sql

select

average