Sets the display format for interval values. The value sql_standard produces output matching SQL standard interval literals. The value postgres produces output matching PostgreSQL releases prior to 8.4 when the DateStyle parameter was set to ISO.

The value postgres_verbose produces output matching Greenplum releases prior to 3.3 when the DateStyle parameter was set to non-ISO output.

The value iso_8601 will produce output matching the time interval format with designators defined in section 4.4.3.2 of ISO 8601. See the PostgreSQL 8.4 documentation for more information.