To ensure compatibility with earlier versions of PostgreSQL, the developers have continued to provide the older datetime and timespan data types. The datetime type is now equivalent to timestamp , while the timespan is now equivalent to the interval types.
Other date/time data types include abstime and reltime , which are lower precision types. However, these types are internal to PostgreSQL, and any or all of these types may disappear in a future release. It is advised therefore to design new applications with the SQL-compliant data types in mind, and to convert older applications from any of these data types as soon as is possible.