The following bug has been logged on the website:
Bug reference: 7824
Logged by: Tim Romano
Email address: tim(dot)romano(at)yahoo(dot)com
PostgreSQL version: 9.2.2
Operating system: Windows 7 x64
Description:
Documentation seems to indicate that only a Timestamp value is a valid
argument to the Extract function when trying to get the DOW, but a Date also
works:
dow
The day of the week (0 - 6; Sunday is 0) (for timestamp values only)
SELECT EXTRACT(DOW FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 5