Get days of week in Postgresql

In Postgres 9 onwards there's:

to_char(date, 'dy');

which would return your date into the day of the week as a text value

Just use extract:

extract(dow from date_column::timestamp)
from whatever_table;

This returns 0 for Sunday, 1 for Monday,...,6 for Saturday.

Edit: Or, since you apparently don't need anything that actually requires grabbing the day of week from a given date and you just want a single column with the fixed string values representing the names of the days of the week, just create a table...