statement ok
CREATE TABLE data (a INT, b INT, c INT, d INT, PRIMARY KEY (a, b, c, d))

# Generate all combinations of values 1 to 3.
statement ok
INSERT INTO data SELECT a, b, c, d FROM
   generate_series(1, 3) AS a(a),
   generate_series(1, 3) AS b(b),
   generate_series(1, 3) AS c(c),
   generate_series(1, 3) AS d(d)

statement ok
SET experimental_hash_group_join_enabled = true

query II rowsort
SELECT data1.a, sum_int(data1.d) FROM data AS data1 INNER HASH JOIN data AS data2 ON data1.a = data2.c GROUP BY data1.a
----
1  1458
2  1458
3  1458

statement ok
RESET experimental_hash_group_join_enabled

# Same query as above, but with the hash group-join disabled.
query II rowsort
SELECT data1.a, sum_int(data1.d) FROM data AS data1 INNER HASH JOIN data AS data2 ON data1.a = data2.c GROUP BY data1.a
----
1  1458
2  1458
3  1458
