create table if not exists my_timeseries as
       select
           coalesce(sector, district, area) as postcode,
           import_date,
           'A'::character(1) as property_type,
           -1::smallint as bedrooms,

           CAST (sum(1) filter(where is_begin_ts) AS REAL) as s_listings,
           CAST (percentile_cont(array[0.25,0.5,0.75,0.9]) within group (order by asking_price) filter(where asking_price > 0) AS REAL[]) as s_price_asked

       from my_source_table
       where import_date <= '2019-05-01'::date
       grouping sets ((sector, import_date), (district, import_date), (area, import_date));