with
    all_polys as (select ...),
    water_polys as (select ... where "natural"='water' or  ...)
select ...
   st_difference(all_polys.geometry, st_union(water_polys.geometry))
...
from all_polys, water_polys
where st_intersects(all_polys.geometry, water_polys.geometry)
group by all_polys.id```