Data update

Task/Collections/DuckDB/collections.duckdb

@@ -0,0 +1,11 @@
+create or replace function toset(l) as
+  array_sort(list_distinct(l));
+
+create or replace function array_intersection(a,b) as
+  array_filter(a, x -> array_contains(b, x));
+
+create or replace function set_union(a,b) as
+  toset(toset(a) || toset(b)));
+
+create or replace function set_intersection(a,b) as
+  array_intersection(toset(a),toset(b));