Get a timestamp from concatenating day and time columns

Question

I am having day and time fields in database. I want to get the time-stamp by concatenating the day and time. How to do this in PostgreSQL?

I have done this:

SELECT EXTRACT(EPOCH FROM TIMESTAMP '2011-05-17 10:40:28');

And it is working fine.

But when I tried replacing day and time fields I am getting the following error:

SELECT EXTRACT(EPOCH FROM TIMESTAMP Day || ' ' || Time);

ERROR:  syntax error at or near "Day"
LINE 1: ...quest_count > 0 AND (EXTRACT(EPOCH FROM TIMESTAMP Day || ' ' || Time)) > (e...

Answer 1

SELECT EXTRACT(EPOCH FROM (Day || ' ' || Time)::timestamp);