SQL Server，T-SQL操作符可以像變量一樣使用嗎？或類似的東西

Question

我想要做的就是這樣的事情

DECLARE @operator nvarchar; 
SET @operator = 'AND' 

SELECT * FROM MyTable 
WHERE first_column = "1" @operator second_columnt = "2" 

有沒有實現這樣的一個邏輯的方法嗎？

Answer 1

你可以做到這一點使用動態SQL：

declare @query varchar(max) 
set @query = 'select * from MyTable where first_column = ''1'' ' + 
    @operator + ' second_column = ''2''' 
exec (@query) 

有時候，where語句的邏輯是足夠的，如：

select * 
from MyTable 
where (operator = 'AND' and first_column = '1' and second_column = '2') 
     or (operator = 'OR' and (first_column = '1' or second_column = '2'))