1. datediff is used in the format: DATEDIFF(datepart, startdate, enddate). Where startdate (start date) and enddate (end date) parameters are legal date expressions.

2, datediff function can be used for SELECT query operation for the query given the number of days between the two dates of the interval.

3, datediff function query start date location does not require, such as the new date can be used as startdate, the old date can be used as enddate, so that the number of days obtained is displayed in negative numbers. deep big data platform datediff use can refer to the above method.