在 sql 中使用日期检查特定天数

Question

i am new in SQL and need help by a task which we got from school. The following task is:

Who has exceeded the permissible borrowing period of 2 weeks

I have already written that code.

select borrow.user_id from borrow where count(return_date - borrow_date) > 14;

I am not really sure what I am doing there. I know that its wrong but yea... I don't really know how to do it.

I hope someone understands my problem and can help... Thanks for your advice

Answer 1

I think you need datediff as follows:

select borrow.user_id, 
       datediff(return_date, borrow_date) - interval 14 day as over_days 
  from borrow where datediff(return_date, borrow_date) > 14;

Answer 2

Use datediff instead of directly subtracting 2 dates

SELECT borrow.user_id
FROM borrow
WHERE DATEDIFF(return_date, borrow_date) > 14;

Check documentation of datediff