mysql - 如何在 1 个查询中使用 COUNT() 和 SUM()

Question

我正在尝试获取学生分数总和以及学生人数

表架构为

Stud_ID|Stud_Name|Marks|Class
1      | A       |20   |1   
1      | A       |10   |1
1      | A       |22   |1
5      | G       |21   |1
5      | G       |16   |1
5      | G       |27   |1
2      | B       |13   |1
2      | B       |14   |1
2      | B       |21   |1
2      | B       |13   |1
2      | B       |21   |1
3      | C       |10   |1
3      | C       |17   |1
3      | C       |16   |1

我需要每个学生的总分以及表格中有多少学生。我正在尝试将 DISTINCT 和 SUM 结合起来，但没有成功

SELECT count(
sum(`mark`) FROM `es_marks_entry_summery` where `class` ='16' group by `Stud_ID`)

Answer 1

DECLARE @Result TABLE (Stud_ID INT, Marks INT)

INSERT INTO @Result(Stud_ID, Marks) SELECT COUNT(Stud_ID), SUM(Marks) from es_marks_entry_summery WHERE Class = '16'

SELECT * FROM @Result