How to get dates that match the names of the days of the week in Postgresql?

Question

PostgreSQL

I have start date, end date and day names.
It is required to find all dates between the beginning and the end that will be on this day.
That is, you need to determine all the dates in the period when it will be Friday or Tuesday.
How can this be done?

Answer 1

select day /*, ... */ 
from tablename 
join lateral generate_series(start_date, end_date, interval '1day') as day on true 
where to_char(day, 'Day') = week_day

if in the forehead and your week_day (which is stored in varchar for a very unclear reason), the spelling coincides with to_char.