mysql 날짜 차이구하기

YYYY-MM-DD 형식

SELECT 
TO_DAYS('2017-01-31') 
- 
TO_DAYS('2017-01-25')
AS result;
 

SELECT 
TO_DAYS('2017-01-31') 
- 
TO_DAYS('2017-01-25')
AS result;
 

서브쿼리 사용도 가능

SELECT 
TO_DAYS((SELECT rental.RETURNDAY from rental WHERE rental.RENTALCODE=1000000)) 
- 
TO_DAYS((SELECT rental.RETURNEXPECTDAY from rental WHERE rental.RENTALCODE=1000000))
AS result;