sql server中这一句怎么没有select

Question

DECLARE @S NVARCHAR(1000)
SELECT @S='SELECT [USER_NAME] AS 姓名'
SELECT @S=@S+',SUM(CASE WHEN COURSE='''+CAST(COURSE AS VARCHAR)+'''THEN SCORE END) AS '+COURSE FROM TEST_TB_GRADE GROUP BY COURSE
SELECT @S=@S+' FROM TEST_TB_GRADE GROUP BY [USER_NAME]'
EXEC(@S)

--这一句怎么没有select
SUM(CASE WHEN COURSE='''+CAST(COURSE AS VARCHAR)+'''THEN SCORE END) AS '+COURSE FROM TEST_TB_GRADE GROUP BY COURSE

Answer 1

这是拼接一个T-sql的字符串

Answer 2

拼接的sql中不是有 select啊

Answer 3

虽然这么说，但他有两个FROM！