How to calculate DATE Difference in PostgreSQL?

Question

Here I need to calculate the difference of the two dates in the PostgreSQL.

In SQL Server: Like we do in SQL Server its muc

Answer 1

Your calculation is correct for DATE types, but if your values are timestamps, you should probably use EXTRACT (or DATE_PART) to be sure to get only the difference in full days;

EXTRACT(DAY FROM MAX(joindate)-MIN(joindate)) AS DateDifference

An SQLfiddle to test with. Note the timestamp difference being 1 second less than 2 full days.