should be it

external/duckdb/test/sql/merge/merge_into_subquery.test

@@ -0,0 +1,45 @@
+# name: test/sql/merge/merge_into_subquery.test
+# description: Test MERGE INTO with subqueries
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Totals(item_id int, balance int);
+
+statement ok
+CREATE TABLE Buy(item_id int, volume int);
+
+statement ok
+INSERT INTO Buy values(10, 1000), (30, 300), (20, 2000);
+
+query I
+MERGE INTO Totals USING (VALUES (10), (30)) Updates(item_id) ON Totals.item_id = Updates.item_id
+WHEN MATCHED THEN UPDATE SET balance = (SELECT SUM(volume) FROM Buy WHERE item_id=Totals.item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (Updates.item_id, (SELECT SUM(volume) FROM Buy WHERE item_id=Updates.item_id));
+----
+2
+
+query II
+FROM Totals ORDER BY ALL
+----
+10	1000
+30	300
+
+statement ok
+INSERT INTO Buy values(10, 2000)
+
+query I
+MERGE INTO Totals USING (VALUES (10), (20)) Updates(item_id) ON Totals.item_id = Updates.item_id
+WHEN MATCHED THEN UPDATE SET balance = (SELECT SUM(volume) FROM Buy WHERE item_id=Totals.item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (Updates.item_id, (SELECT SUM(volume) FROM Buy WHERE item_id=Updates.item_id));
+----
+2
+
+query II
+FROM Totals ORDER BY ALL
+----
+10	3000
+20	2000
+30	300