should be it

external/duckdb/test/sql/window/test_window_interval.test

@@ -0,0 +1,34 @@
+# name: test/sql/window/test_window_interval.test
+# description: Test window functions with intervals
+# group: [window]
+
+statement ok
+PRAGMA enable_verification
+
+# interval as group
+statement ok
+create table a as select case when range%2==0 then interval '1 year' else interval '2 years' end j, range::integer AS i from range(1, 5, 1)
+
+query III
+select j, i, sum(i) over () from a order by 1,2
+----
+1 year	2	10
+1 year	4	10
+2 years	1	10
+2 years	3	10
+
+query III
+select j, i, sum(i) over (partition by j) from a order by 1,2
+----
+1 year	2	6
+1 year	4	6
+2 years	1	4
+2 years	3	4
+
+query III
+select j, i, sum(i) over (partition by j order by i) from a order by 1,2
+----
+1 year	2	2
+1 year	4	6
+2 years	1	1
+2 years	3	4