Datetime Data Types (1)

• TIMESTAMP : Date with fractional second
  
• INTERVAL YEAR TO MONTH : Stored as an interval of years and months
  
• INTERVAL DAY TO SECOND : Stored as an interval of days, hours, minutes and seconds
  

Representing the Difference Between Datetime Values

Use the INTERVAL DAY TO SECOND datatype to represent the precise difference between two datetime values. For example, you might use this value to set a reminder for a time 36 hours in the future or to record the time between the start and end of a race. To represent long spans of time with high precision, you can use a large value for the days portion.

Use the INTERVAL YEAR TO MONTH datatype to represent the difference between two datetime values, where the only significant portions are the year and the month. For example, you might use this value to set a reminder for a date 18 months in the future, or check whether 6 months have elapsed since a particular date.

Oracle Database stores dates in its own internal format. Date data is stored in fixed-length fields of seven bytes each, corresponding to century, year, month, day, hour, minute, and second.