如何解决此错误（关键字“SELECT”附近的语法不正确。）

Question

My query is :

DECLARE @Date DATETIME2
DECLARE @Number INT
DECLARE @Number2 INT

SET @Number = 90
SET @Number2 = 89

SET @Num = @Number - @Number2

SET @Date = SELECT TOP (@Num) YEAR(Tarikh) FROM Final 

Answer 1

You need to either put your SELECT subquery into brackets like this:

DECLARE @Date DATETIME2   -- this should *really* be an `INT` ....   
SET @Date = (SELECT TOP (@Num) YEAR(Tarikh) FROM Final)  -- YEAR(..) returns *INT* !

or you need to rewrite this as a SELECT only statement - like this:

SELECT TOP (@Num) @Date = YEAR(Tarikh) 
FROM Final 
-- ORDER BY ......   -- you should *REALLY* include an ORDER BY for TOP to make any sense....

Of course, this only works if your subquery always returns only ONE possible value!

And also : using the TOP clause without an explicit ORDER BY clause is kinda dangerous - since you're not explicitly telling SQL Server which TOP row you want, you might get any arbitrary row(s) ...

And lastly : using YEAR(...) returns an INT value - which you're assigning to a DATETIME2 variable ...... that doesn't really make any sense at all.......