How to find out the weekday from a date???

Hello PG's,

I want to extract the weekday of a given 'date' type field in my table
when selecting. How can I do this?

For example in a table "bschft_days" filled with values with type 'date'

I want to select all the days within the month 'march' and output the respective
weekday. I tryed this:

select extract(dow from timestamp(day)), day, userid from bschft_days where date_part('month', day) = '3';

But it only tells me:

ERROR: parser: parse error at or near "dow"

:(

Any ideas??

Thanks a lot in advance!

Best Regards / Mit freundlichen Grüßen / Un saludo

José Manuel lorenzo López