In this example, the tswz column in table1 contains the following timestamp data:
SELECT * FROM table1;
The result of the query is:
tswz ----------------------------------- 2011-11-04 13:14:00.860000-07:00
You can use an AT clause with a time zone string in a SELECT query to get the same time in a different time zone. For example:
SELECT CAST(tswz AS TIMESTAMP WITH TIME ZONE AT 'gmt') FROM table1;
The result of the query is:
tswz ----------------------------------- 2011-11-04 20:14:00.860000+00:00
Similarly, you can use an AT clause with a time zone displacement to get the same result.
SELECT CAST(tswz AS TIMESTAMP WITH TIME ZONE AT TIME ZONE '00:00') FROM table1;
The result of the query is:
tswz ----------------------------------- 2011-11-04 20:14:00.860000+00:00
The following query produces the same result without an explicit CAST:
SELECT tswz AT 'gmt' FROM table1;
The result of the query is:
tswz AT TIME ZONE 'gmt' ----------------------------------- 2011-11-04 20:14:00.860000+00:00