Sql Group by 使用

 

CREATE TABLE StuCourseScore
(
ID int, 
Name nvarchar(10),
Course nvarchar(10),
Score int
)
INSERT StuCourseScore VALUES(1,'张三','语文',80)
INSERT StuCourseScore VALUES(1,'张三','数学',89)
INSERT StuCourseScore VALUES(1,'张三','英语',90)

INSERT StuCourseScore VALUES(2,'李四','语文',100)
INSERT StuCourseScore VALUES(2,'李四','数学',79)
INSERT StuCourseScore VALUES(2,'李四','英语',95)

SELECT * FROM StuCourseScore

SELECT --group的字段或者聚合函数
	ID, 
	sum(
	case
		when Course='语文' then Score
	end) as "语文成绩",
	sum(
	case
		when Course='数学' then Score
	end) as "数学成绩",
	sum(
	case
		when Course='英语' then Score
	end) as "英语成绩"
FROM StuCourseScore
GROUP BY ID

--以后名字加上
SELECT Name FROM StuCourseScore
group BY Name