Date comparison in PostgreSQL

Question

Is there a way to compare two dates in the same table like this:

SELECT * FROM mytable WHERE date_1 = date_2;

I am looking for the simplest approach to do this as part of an update statement.

Solution

Yes, you can do that. Simple as that.

Have a look at the date / time data types in PostgreSQL.

You may have to pay special attention if your "date", in fact, is a timestamp. By default up to 6 fractional digits are saved, can be tricky with the equality operator. You might cast to timestamp(0) to round to seconds or use date_trunc() to truncate to one of various time units.