如何使用sql server 2008從變量中選擇最上面一行？

Question

我們可以從變量值中選擇最上面的行嗎？在sql server 2008中？像這樣。

declare @rows int=2; 
    select top @rows * from table_name; 
-- instead of select top 2 * from table_name; 

Answer 1

你快到了。

declare @rows int=2; 
select top (@rows) * from table_name; 

Answer 2

你也可以試試這個。

declare @rows int=2; 
declare @query varchar(200)= 'select top ' + cast(@rows as varchar(4))+ ' * from TBLB_Order'; 
exec (@query); 

Answer 3

declare @rows int=2; 
select top @rows percent * from table_name;