sql - monetdb 中的日期查询？

Question

我能够执行以下查询

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

但我无法用变量代替“1”。我尝试了以下方法但没有成功

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;

我也尝试过铸造，但仍然没有结果。

Answer 1

我找到了解决方案：

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;

所以这个问题得到了回答:)