[joeclark77]

This would have been real useful to me about a week ago as I was writing several of these types of queries!

On the debate of "timestamp vs timestamptz" I reached the opposite conclusion of the author: I've got Amazon RDS instances set to UTC and my timestamps are stored as UTC times with no timezone awareness. Instead, I add the timezone while querying. I think this is better because I never have to remember anything about server settings!

I discovered that the `AT TIME ZONE` clause has two meanings, so I sometimes have to use it twice. In this example which selects all records created this month:

    ...WHERE create_date  AT TIME ZONE 'UTC' AT TIME ZONE 'America/New_York' > date_trunc('month',current_date)

the first occurrence of `AT TIME ZONE` tells postgres that the timestamp is in UTC (which it is) and the second occurrence subtracts four or five hours (depending on daylight savings time) to show New York time. If I only had the second such clause it would subtract that many hours... it would think I was giving it a New York timestamp and I wanted to see the UTC time.