在monetdb中查询日期？

Question

我能做到下面的查询

select (current_date-interval '1' day) ,a,b from (select '1' as a, 2 as b) as t2; 

但我不能够把变量代替“1”。 我曾尝试没有成功

select (current_date-interval b day) ,a,b from (select '1' as a, 2 as b) as t2; 
select (current_date-interval a day) ,a,b from (select '1' as a, 2 as b) as t2; 

我也曾尝试铸造，但还是没有结果下面的方法。

Answer 1

我找到了解决这个：

select (current_date-interval 1 day*b) ,a,b from (select '1' as a, 2 as b) as t2; 
select (current_date-interval 1 day*cast(a as int)) ,a,b from (select '1' as a, 2 as b) as t2; 

所以对这一问题的回答:)