DATEADD,DATEDIFF

MSDN 날짜및 시간

https://docs.microsoft.com/ko-kr/sql/t-sql/functions/date-and-time-data-types-and-functions-transact-sql

DATEADD

https://msdn.microsoft.com/ko-kr/library/ms186819(v=sql.120).aspx

DATEADD(datepart,number,date)

30일 더하기

SELECT DATEADD(d,30,getdate())

등록된 날에 30일더한날이 오늘보다 크다면 출력

SELECT * FROM SAMPLE_TABLE

WHERE DATEADD(d,30,원하는날짜) >= getdate()

시간은 제외하고 날짜로 체크하기위해서 DATEDIFF사용

DATEDIFF

https://docs.microsoft.com/ko-kr/sql/t-sql/functions/datediff-transact-sql

DATEDIFF(datepart,startdate,enddate)

SELECT * FROM SAMPLE_TABLE

WHERE DATEDIFF ( day , DATEADD(d,30,원하는날짜) , getdate() ) <= 0