SQL statement for mysql time operations

SQL statement for mysql time operations select * from mytest where (select DATEDIFF (now (), current) = 0); // SELECT OrderId, DATE_ADD (OrderDate, INTERVAL 2 DAY) AS OrderPayDateFROM Orders add 2 days to "OrderDate" and the result is 16:25:46. 635 SELECT OrderId, DATE_SUB (OrderDate, INTERVAL 2 DAY) AS OrderPayDateFROM Orders minus two days from "OrderDate" Result: 16:25:46. 635 the DATEDIFF () function returns the number of days between two dates. The date1 and date2 parameters are valid date or date/time expressions. Note: Only the date part of the value is involved in calculation. Select datediff ('2014-12-30 ', '2014-12-29') AS DiffDate result 1 select datediff ('2014-12-29 ', '2014-12-30') AS DiffDate result-1