Don’t you want toWeek to be 1 greater than fromWeek? If so your where clauses should be:
... and fromWeek <= date_part(w, current_date - interval '6 weeks') and toWeek >= date_part(w, current_date - interval '5 weeks') ...
I suspect you just don’t have data for values for toWeek that are high enough to pass your toWeek where clause.
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