sql服务器将选择的结果存储在变量中？

Question

我在做一个功能。一个select语句只返回一列和一列，比如一个int。我如何将这个int存储在一个声明的变量中，以便我的函数可以返回变量？

select sum(table_name.col1) -- this line returns only one int. How to store that 
--in a declared variable ? 
from 
(select 
col1, col2 
--code here 
)table_name 

Answer 1

DECLARE @Varname int 
SELECT @Varname = SUM(table_name.col1) FROM etc 
SELECT @Varname 

Answer 2

DECLARE @result INT 

SELECT @result = sum(table_name.col1) 
from 
(select 
col1, col2 
--code here 
)table_name