Last week Warren left a comment on my story Converting Time Zones in Oracle asking how he could output dates with time zone like: “17-Mar-2006 14:30:00 EST”.
Well, after a bit of digging it turns out the answer is not as simple as it sounds. The traditional Oracle
TIMESTAMP datatypes don’t store time zone information. A workaround might be to store time zone information in a separate column in the table, but that seems like it could cause some confusion.
Well, it looks like in version 9i Oracle has added a new datatype to handle exactly this. The
TIMESTAMP WITH TIME ZONE datatype allows a time zone to be stored with a date and time either in offset from UTC or by abbreviation.
TIMESTAMP WITH TIME ZONE datatype can be declared in the table definition anywhere you would have used
TIMESTAMP. To store a date/time/time zone into a row Oracle has also added the function
TO_TIMESTAMP_TZ which acts much like the familiar TO_DATE function, however will recognize
TZD for time zone hour, minute, region, and abbreviation respectively.
To retrieve time zone information you can apply the same new abbreviations to the familiar to_char function when selecting a column of type
TIMESTAMP WITH TIME ZONE.
Rather than go into any more detail here, check out this article from Oracle Magazine. It covers the topic very well including example code.