should be it

external/duckdb/test/sql/merge/merge_into.test

@@ -0,0 +1,117 @@
+# name: test/sql/merge/merge_into.test
+# description: Test MERGE INTO
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int);
+
+statement ok
+CREATE TABLE Buy(item_id int, volume int);
+
+statement ok
+INSERT INTO Buy values(10, 1000);
+
+statement ok
+INSERT INTO Buy values(30, 300);
+
+# insert using merge into with a CTE
+query I
+WITH initial_stocks(item_id, balance) AS (VALUES (10, 2200), (20, 1900))
+MERGE INTO Stock USING initial_stocks ON FALSE
+WHEN MATCHED THEN DO NOTHING
+WHEN NOT MATCHED THEN INSERT VALUES (initial_stocks.item_id, initial_stocks.balance)
+----
+2
+
+# DO NOTHING is the default - this is a nop
+query I
+WITH initial_stocks(item_id, balance) AS (VALUES (10, 2200), (20, 1900))
+MERGE INTO Stock USING initial_stocks USING (item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (item_id, initial_stocks.balance)
+----
+0
+
+query II
+FROM Stock ORDER BY item_id
+----
+10	2200
+20	1900
+
+# update and insert
+query I
+MERGE INTO Stock AS s USING Buy AS b ON s.item_id = b.item_id
+WHEN MATCHED THEN UPDATE SET balance = balance + b.volume
+WHEN NOT MATCHED THEN INSERT VALUES (b.item_id, b.volume)
+----
+2
+
+query II
+FROM Stock ORDER BY item_id
+----
+10	3200
+20	1900
+30	300
+
+# sell - deleting all rows that are fully sold
+statement ok
+CREATE TABLE Sale(item_id int, volume int);
+
+statement ok
+INSERT INTO Sale VALUES (10, 2200);
+
+statement ok
+INSERT INTO Sale VALUES (20, 1900);
+
+query I
+MERGE INTO Stock USING Sale ON Stock.item_id = Sale.item_id
+WHEN MATCHED AND Sale.volume > balance THEN ERROR
+WHEN MATCHED AND Sale.volume = balance THEN DELETE
+WHEN MATCHED AND TRUE THEN UPDATE SET balance = balance - Sale.volume
+WHEN MATCHED THEN ERROR
+WHEN NOT MATCHED THEN ERROR
+----
+2
+
+query II
+FROM Stock ORDER BY item_id
+----
+10	1000
+30	300
+
+# abort - row does not exist
+statement error
+MERGE INTO Stock USING Sale ON Stock.item_id = Sale.item_id
+WHEN MATCHED AND Sale.volume >= balance THEN DELETE
+WHEN MATCHED THEN UPDATE SET balance = balance - Sale.volume
+WHEN NOT MATCHED THEN ERROR CONCAT('Sale item with item id ', Sale.item_id, ' not found');
+----
+Sale item with item id 20 not found
+
+# we need to specify at least one match action
+statement error
+WITH initial_stocks(item_id, balance) AS (VALUES (10, 2200), (20, 1900))
+MERGE INTO Stock USING initial_stocks ON (Stock.item_id = initial_stocks.item_id)
+----
+Parser
+
+# we cannot specify an unconditional WHEN NOT MATCHED clause
+statement error
+WITH initial_stocks(item_id, balance) AS (VALUES (10, 2200), (20, 1900))
+MERGE INTO Stock USING initial_stocks ON (Stock.item_id = initial_stocks.item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (initial_stocks.item_id, initial_stocks.balance)
+WHEN NOT MATCHED THEN ERROR;
+----
+only one unconditional WHEN NOT MATCHED clause
+
+# we cannot merge into views
+statement ok
+CREATE VIEW my_view AS SELECT 42 item_id
+
+statement error
+MERGE INTO my_view USING Sale ON my_view.item_id = Sale.item_id
+WHEN NOT MATCHED THEN INSERT
+----
+base tables

external/duckdb/test/sql/merge/merge_into_by_source.test

@@ -0,0 +1,42 @@
+# name: test/sql/merge/merge_into_by_source.test
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int);
+
+statement ok
+INSERT INTO Stock VALUES (5, 10), (10, 20), (20, 30);
+
+# WHEN NOT MATCHED BY SOURCE
+# basically, this turns "Stock" into "new_accounts"
+# -> if we have a match we update to the new value
+# -> if we have a row in new_accounts that does not exist in Stock, insert it
+# -> if we have a row in Stock that does not exist in new_accounts, delete it
+query I
+MERGE INTO Stock USING (VALUES (5, 20), (10, 30)) new_accounts(item_id, balance) USING (item_id)
+WHEN MATCHED THEN UPDATE
+WHEN NOT MATCHED BY TARGET THEN INSERT
+WHEN NOT MATCHED BY SOURCE THEN DELETE
+----
+3
+
+query II
+FROM Stock ORDER BY ALL
+----
+5	20
+10	30
+
+# WHEN NOT MATCHED BY SOURCE only
+query I
+MERGE INTO Stock USING (VALUES (10)) new_accounts(item_id) USING (item_id)
+WHEN NOT MATCHED BY SOURCE THEN DELETE
+----
+1
+
+query II
+FROM Stock ORDER BY ALL
+----
+10	30

external/duckdb/test/sql/merge/merge_into_constraint.test

@@ -0,0 +1,48 @@
+# name: test/sql/merge/merge_into_constraint.test
+# description: Test MERGE INTO with constraints
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int NOT NULL, balance int, CHECK (balance>0));
+
+statement error
+MERGE INTO Stock USING (VALUES (NULL, NULL)) new_accounts(item_id, balance) USING (item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (new_accounts.item_id, new_accounts.balance)
+----
+NOT NULL constraint
+
+statement ok
+MERGE INTO Stock USING (VALUES (1, 10)) new_accounts(item_id, balance) USING (item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (new_accounts.item_id, new_accounts.balance)
+
+# trying to delete too much
+statement error
+MERGE INTO Stock USING (VALUES (1, 15)) sales(item_id, volume) USING (item_id)
+WHEN MATCHED THEN UPDATE SET balance = balance - volume
+----
+CHECK constraint
+
+# binding with check constraints
+statement ok
+CREATE TABLE Items(item_id int NOT NULL, total_cost INTEGER, base_cost INTEGER, tax_cost INTEGER, CHECK (total_cost = base_cost + tax_cost));
+
+statement ok
+INSERT INTO Items VALUES (1, 10, 8, 2);
+
+statement error
+MERGE INTO Items USING (VALUES (1, 15)) new_prices(item_id, total_cost) USING (item_id)
+WHEN MATCHED THEN UPDATE SET total_cost = new_prices.total_cost
+----
+CHECK constraint
+
+statement ok
+MERGE INTO Items USING (VALUES (1, 15)) new_prices(item_id, total_cost) USING (item_id)
+WHEN MATCHED THEN UPDATE SET total_cost = new_prices.total_cost, base_cost = new_prices.total_cost - 2
+
+query IIII
+FROM Items
+----
+1	15	13	2

external/duckdb/test/sql/merge/merge_into_default.test

@@ -0,0 +1,55 @@
+# name: test/sql/merge/merge_into_default.test
+# description: Test MERGE INTO with default values
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int DEFAULT 0);
+
+# explicit default
+query I
+MERGE INTO Stock USING (VALUES (10)) new_accounts(item_id) USING (item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (new_accounts.item_id, DEFAULT)
+----
+1
+
+# column list
+query I
+MERGE INTO Stock USING (VALUES (20)) new_accounts(item_id) USING (item_id)
+WHEN NOT MATCHED THEN INSERT (item_id) VALUES (new_accounts.item_id)
+----
+1
+
+# default values
+query I
+MERGE INTO Stock USING (VALUES (30)) new_accounts(item_id) USING (item_id)
+WHEN NOT MATCHED THEN INSERT DEFAULT VALUES
+----
+1
+
+query II
+FROM Stock
+----
+10	0
+20	0
+NULL	0
+
+statement ok
+UPDATE Stock SET balance=100
+
+# update default
+query I
+MERGE INTO Stock USING (VALUES (10)) reset_accounts(item_id) USING (item_id)
+WHEN MATCHED THEN UPDATE SET balance=DEFAULT
+WHEN NOT MATCHED THEN ERROR
+----
+1
+
+query II
+FROM Stock
+----
+10	0
+20	100
+NULL	100

external/duckdb/test/sql/merge/merge_into_error.test

@@ -0,0 +1,30 @@
+# name: test/sql/merge/merge_into_error.test
+# description: Test MERGE INTO with error in condition
+# group: [merge]
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int);
+
+statement ok
+CREATE TABLE Buys(item_id int, volume int);
+
+statement ok
+INSERT INTO Buys VALUES (42, 100);
+
+query I
+MERGE INTO Stock USING Buys USING (item_id)
+WHEN NOT MATCHED AND true THEN INSERT
+WHEN NOT MATCHED AND error('this should not be executed') THEN INSERT
+WHEN NOT MATCHED THEN ERROR
+----
+1
+
+query I
+SELECT COUNT(*) FROM Stock
+----
+1
+
+query II
+FROM Stock
+----
+42	100

external/duckdb/test/sql/merge/merge_into_index.test

@@ -0,0 +1,26 @@
+# name: test/sql/merge/merge_into_index.test
+# description: Test MERGE INTO with an index
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Accounts(id INTEGER, username VARCHAR PRIMARY KEY, favorite_numbers INT[]);
+
+statement ok
+INSERT INTO Accounts VALUES (1, 'user1', NULL)
+
+query I
+MERGE INTO Accounts USING (
+	VALUES (1, 'user2', [1, 2, 3])
+) new_account(id) USING (id)
+WHEN MATCHED THEN UPDATE
+WHEN NOT MATCHED THEN INSERT
+----
+1
+
+query III
+FROM Accounts WHERE username='user2'
+----
+1	user2	[1, 2, 3]

external/duckdb/test/sql/merge/merge_into_insert_star.test

@@ -0,0 +1,49 @@
+# name: test/sql/merge/merge_into_insert_star.test
+# description: Test MERGE INTO INSERT *
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int DEFAULT 0);
+
+query I
+MERGE INTO Stock USING (VALUES (5, 10)) new_accounts(item_id, balance) USING (item_id)
+WHEN NOT MATCHED THEN INSERT *
+----
+1
+
+query I
+MERGE INTO Stock USING (VALUES (6, 12)) new_accounts(item_id, balance) USING (item_id)
+WHEN NOT MATCHED THEN INSERT
+----
+1
+
+query I
+MERGE INTO Stock USING (VALUES (0, 7)) new_accounts(balance, item_id) USING (item_id)
+WHEN NOT MATCHED THEN INSERT BY NAME
+----
+1
+
+# name mismatch
+statement error
+MERGE INTO Stock USING (VALUES (0, 7)) new_accounts(balanc, item_id) USING (item_id)
+WHEN NOT MATCHED THEN INSERT BY NAME
+----
+balance
+
+# missing column
+query I
+MERGE INTO Stock USING (VALUES (12)) new_accounts(item_id) USING (item_id)
+WHEN NOT MATCHED THEN INSERT BY NAME
+----
+1
+
+query II
+FROM Stock
+----
+5	10
+6	12
+7	0
+12	0

external/duckdb/test/sql/merge/merge_into_multiple_inserts.test_slow

@@ -0,0 +1,34 @@
+# name: test/sql/merge/merge_into_multiple_inserts.test_slow
+# description: Test MERGE INTO with multiple inserts
+# group: [merge]
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int);
+
+statement ok
+CREATE TABLE Buys(item_id int, volume int);
+
+statement ok
+INSERT INTO Buys SELECT i, (random() * 100)::INT FROM range(1000000) t(i);
+
+query I
+MERGE INTO Stock USING Buys USING (item_id)
+WHEN MATCHED THEN ERROR
+WHEN NOT MATCHED BY TARGET AND random() < 0.3 THEN INSERT
+WHEN NOT MATCHED BY TARGET AND random() < 0.3 THEN INSERT
+WHEN NOT MATCHED BY TARGET THEN INSERT
+----
+1000000
+
+query I
+SELECT COUNT(*) FROM Stock
+----
+1000000
+
+query II
+FROM Buys EXCEPT FROM Stock
+----
+
+query II
+FROM Stock EXCEPT FROM Buys
+----

external/duckdb/test/sql/merge/merge_into_multiple_updates.test

@@ -0,0 +1,46 @@
+# name: test/sql/merge/merge_into_multiple_updates.test
+# description: Test MERGE INTO with multiple different update clauses
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Entry(type varchar, number int, text varchar, country VARCHAR, date DATE);
+
+statement ok
+INSERT INTO Entry VALUES
+	('number', 50, NULL, NULL, NULL),
+	('text', NULL, 'Hello', NULL, NULL),
+	('country', NULL, NULL, 'Netherlands', NULL),
+	('date', NULL, NULL, NULL, DATE '2000-01-01');
+
+
+statement ok
+CREATE TABLE NewEntry(type varchar, number int, text varchar, country VARCHAR, date DATE);
+
+statement ok
+INSERT INTO NewEntry VALUES
+	('number', 100, NULL, NULL, NULL),
+	('text', NULL, 'World', NULL, NULL),
+	('country', NULL, NULL, 'Germany', NULL),
+	('date', NULL, NULL, NULL, DATE '2010-01-01');
+
+
+query I
+MERGE INTO Entry USING NewEntry ON Entry.type=NewEntry.type
+WHEN MATCHED AND Entry.type='number' THEN UPDATE SET number=NewEntry.number
+WHEN MATCHED AND Entry.type='text' THEN UPDATE SET text=NewEntry.text
+WHEN MATCHED AND Entry.type='country' THEN UPDATE SET country=NewEntry.country
+WHEN MATCHED AND Entry.type='date' THEN UPDATE SET date=NewEntry.date
+WHEN MATCHED THEN ERROR
+----
+4
+
+query IIIII
+FROM Entry ORDER BY type
+----
+country	NULL	NULL	Germany	NULL
+date	NULL	NULL	NULL	2010-01-01
+number	100	NULL	NULL	NULL
+text	NULL	World	NULL	NULL

external/duckdb/test/sql/merge/merge_into_parenthesis_bug.test

@@ -0,0 +1,37 @@
+# name: test/sql/merge/merge_into_parenthesis_bug.test
+# description: Test MERGE issue when condition is in parenthesis
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE my_timeseries (ts TIMESTAMP, x DOUBLE PRECISION, y DOUBLE PRECISION);
+
+statement ok
+insert into my_timeseries VALUES ('2025-09-15', 43, 39)
+
+statement ok
+CREATE TABLE my_timeseries_new (ts TIMESTAMP, x DOUBLE PRECISION, y DOUBLE PRECISION);
+
+statement ok
+insert into my_timeseries_new VALUES ('2025-09-15', 43, 39)
+
+statement ok
+MERGE INTO my_timeseries old
+    USING my_timeseries_new new
+    ON (
+        old.x = new.x AND
+         (  old.ts != new.ts
+            OR old.x = 1
+        )
+    )
+WHEN MATCHED THEN UPDATE;
+
+statement ok
+MERGE INTO my_timeseries old
+    USING my_timeseries_new new
+    USING(ts)
+WHEN MATCHED AND (
+    old.x  IS DISTINCT FROM new.y
+) THEN UPDATE;

external/duckdb/test/sql/merge/merge_into_returning.test

@@ -0,0 +1,77 @@
+# name: test/sql/merge/merge_into_returning.test
+# description: Test MERGE INTO with RETURNING
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int);
+
+statement ok
+CREATE TABLE Buy(item_id int, volume int);
+
+statement ok
+INSERT INTO Buy values(10, 1000);
+
+statement ok
+INSERT INTO Buy values(30, 300);
+
+# basic returning
+query III
+WITH initial_stocks(item_id, balance) AS (VALUES (10, 2200), (20, 1900))
+MERGE INTO Stock USING initial_stocks ON FALSE
+WHEN MATCHED THEN DO NOTHING
+WHEN NOT MATCHED THEN INSERT VALUES (initial_stocks.item_id, initial_stocks.balance)
+RETURNING merge_action, *
+----
+INSERT	10	2200
+INSERT	20	1900
+
+# do nothing returns nothing
+query II
+WITH initial_stocks(item_id, balance) AS (VALUES (10, 2200), (20, 1900))
+MERGE INTO Stock USING initial_stocks ON (Stock.item_id = initial_stocks.item_id)
+WHEN NOT MATCHED THEN INSERT VALUES (initial_stocks.item_id, initial_stocks.balance)
+RETURNING *
+----
+
+# update and insert
+query III
+MERGE INTO Stock AS s USING Buy AS b ON s.item_id = b.item_id
+WHEN MATCHED THEN UPDATE SET balance = balance + b.volume
+WHEN NOT MATCHED THEN INSERT VALUES (b.item_id, b.volume)
+RETURNING *, merge_action;
+----
+10	3200	UPDATE
+30	300	INSERT
+
+# sell - deleting all rows that are fully sold
+statement ok
+CREATE TABLE Sale(item_id int, volume int);
+
+statement ok
+INSERT INTO Sale VALUES (10, 2200);
+
+statement ok
+INSERT INTO Sale VALUES (20, 1900);
+
+query III
+MERGE INTO Stock USING Sale ON Stock.item_id = Sale.item_id
+WHEN MATCHED AND Sale.volume > balance THEN ERROR
+WHEN MATCHED AND Sale.volume = balance THEN DELETE
+WHEN MATCHED AND TRUE THEN UPDATE SET balance = balance - Sale.volume
+WHEN MATCHED THEN ERROR
+WHEN NOT MATCHED THEN ERROR
+RETURNING Stock.item_id, merge_action, Stock.balance
+----
+20	DELETE	1900
+10	UPDATE	1000
+
+query III
+WITH deleted_stocks(item_id) AS (VALUES (30))
+MERGE INTO Stock USING deleted_stocks ON Stock.item_id = deleted_stocks.item_id
+WHEN MATCHED THEN DELETE
+RETURNING *, merge_action;
+----
+30	300	DELETE

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

external/duckdb/test/sql/merge/merge_into_too_few_columns.test

@@ -0,0 +1,21 @@
+# name: test/sql/merge/merge_into_too_few_columns.test
+# description: Test MERGE INTO with too few columns
+# group: [merge]
+
+statement ok
+CREATE TABLE people (id INTEGER, name VARCHAR, salary FLOAT);
+
+statement ok
+INSERT INTO people VALUES (1, 'John', 92_000.0), (2, 'Anna', 100_000.0);
+
+statement error
+MERGE INTO people
+USING (
+	SELECT
+		3 AS id,
+		89_000.0 AS salary
+) AS upserts
+ON (upserts.id = people.id)
+WHEN NOT MATCHED THEN INSERT;
+----
+has 3 columns but 2 values were supplied

external/duckdb/test/sql/merge/merge_into_tpch.test_slow

@@ -0,0 +1,55 @@
+# name: test/sql/merge/merge_into_tpch.test_slow
+# description: Test merge into with TPC-H SF1
+# group: [merge]
+
+require tpch
+
+statement ok
+CALL dbgen(sf=1);
+
+foreach it no_index index
+
+statement ok
+CREATE TABLE random_lineitem AS FROM lineitem LIMIT 0
+
+onlyif it=index
+statement ok
+ALTER TABLE random_lineitem ADD PRIMARY KEY (l_orderkey, l_linenumber);
+
+# create lineitem but with a random subset of the rows
+statement ok
+MERGE INTO random_lineitem USING lineitem USING (l_orderkey, l_linenumber)
+WHEN NOT MATCHED AND random() < 0.2 THEN INSERT
+
+# insert a bunch of rows with unchanged values
+statement ok
+MERGE INTO random_lineitem USING (SELECT * REPLACE (l_orderkey + 10000000 AS l_orderkey) FROM lineitem) USING (l_orderkey, l_linenumber)
+WHEN MATCHED THEN ERROR
+WHEN NOT MATCHED AND random() < 0.2 THEN INSERT
+
+# randomly update a bunch of rows
+statement ok
+MERGE INTO random_lineitem USING lineitem USING (l_orderkey, l_linenumber)
+WHEN MATCHED AND random() < 0.1 THEN UPDATE SET l_discount = random()
+WHEN MATCHED AND random() < 0.1 THEN UPDATE SET l_tax = random()
+
+# run a merge that should fully equalize the tables
+statement ok
+MERGE INTO random_lineitem USING lineitem USING (l_orderkey, l_linenumber)
+WHEN MATCHED THEN UPDATE
+WHEN NOT MATCHED BY TARGET THEN INSERT
+WHEN NOT MATCHED BY SOURCE THEN DELETE
+
+# both tables should now be identical - despite all the random stuff we did
+query IIIIIIIIIIIIIIII
+FROM lineitem EXCEPT FROM random_lineitem
+----
+
+query IIIIIIIIIIIIIIII
+FROM random_lineitem EXCEPT FROM lineitem
+----
+
+statement ok
+DROP TABLE random_lineitem
+
+endloop

external/duckdb/test/sql/merge/merge_into_tpch_by_name.test_slow

@@ -0,0 +1,60 @@
+# name: test/sql/merge/merge_into_tpch_by_name.test_slow
+# description: Test merge into by name TPC-H SF1
+# group: [merge]
+
+require tpch
+
+statement ok
+CALL dbgen(sf=0.1);
+
+foreach it index no_index
+
+# create random_lineitem with columns in random order
+statement ok
+CREATE TABLE random_lineitem AS SELECT l_tax, l_returnflag, l_partkey, l_shipmode, l_discount, l_quantity, l_shipdate, l_extendedprice, l_receiptdate, l_suppkey, l_comment, l_linenumber, l_commitdate, l_orderkey, l_linestatus, l_shipinstruct
+FROM lineitem LIMIT 0
+
+onlyif it=index
+statement ok
+ALTER TABLE random_lineitem ADD PRIMARY KEY (l_orderkey, l_linenumber);
+
+# create lineitem but with a random subset of the rows
+statement ok
+MERGE INTO random_lineitem USING lineitem USING (l_orderkey, l_linenumber)
+WHEN NOT MATCHED AND random() < 0.2 THEN INSERT BY NAME
+
+# insert a bunch of rows with unchanged values
+statement ok
+MERGE INTO random_lineitem USING (SELECT * REPLACE (l_orderkey + 10000000 AS l_orderkey) FROM lineitem) USING (l_orderkey, l_linenumber)
+WHEN MATCHED THEN ERROR
+WHEN NOT MATCHED AND random() < 0.2 THEN INSERT BY NAME
+
+# randomly update a bunch of rows
+statement ok
+MERGE INTO random_lineitem USING lineitem USING (l_orderkey, l_linenumber)
+WHEN MATCHED AND random() < 0.1 THEN UPDATE SET l_discount = random()
+WHEN MATCHED AND random() < 0.1 THEN UPDATE SET l_tax = random()
+
+# run a merge that should fully equalize the tables
+statement ok
+MERGE INTO random_lineitem USING lineitem USING (l_orderkey, l_linenumber)
+WHEN MATCHED THEN UPDATE BY NAME
+WHEN NOT MATCHED BY TARGET THEN INSERT BY NAME
+WHEN NOT MATCHED BY SOURCE THEN DELETE
+
+# both tables should now be identical - despite all the random stuff we did
+query IIIIIIIIIIIIIIII
+FROM lineitem
+EXCEPT
+SELECT l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity, l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate, l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment FROM random_lineitem
+----
+
+query IIIIIIIIIIIIIIII
+SELECT l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity, l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate, l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment FROM random_lineitem
+EXCEPT FROM lineitem
+----
+
+statement ok
+DROP TABLE random_lineitem
+
+endloop

external/duckdb/test/sql/merge/merge_into_update_star.test

@@ -0,0 +1,51 @@
+# name: test/sql/merge/merge_into_update_star.test
+# description: Test MERGE INTO UPDATE *
+# group: [merge]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE Stock(item_id int, balance int DEFAULT 0);
+
+statement ok
+INSERT INTO Stock (item_id) VALUES (5), (10), (20);
+
+# UPDATE star
+query I
+MERGE INTO Stock USING (VALUES (5, 10)) new_accounts(item_id) USING (item_id)
+WHEN MATCHED THEN UPDATE
+----
+1
+
+query I
+MERGE INTO Stock USING (VALUES (10, 30)) new_accounts(item_id, balance) USING (item_id)
+WHEN MATCHED THEN UPDATE SET *
+----
+1
+
+query I
+MERGE INTO Stock USING (VALUES (100, 20)) new_accounts(balance, item_id) USING (item_id)
+WHEN MATCHED THEN UPDATE BY NAME
+----
+1
+
+query II
+FROM Stock
+----
+5	10
+10	30
+20	100
+
+# column mismatches
+statement error
+MERGE INTO Stock USING (VALUES (10)) new_accounts(item_id) USING (item_id)
+WHEN MATCHED THEN UPDATE SET *
+----
+not match column count
+
+statement error
+MERGE INTO Stock USING (VALUES (10, 20)) new_accounts(item_id, balanc) USING (item_id)
+WHEN MATCHED THEN UPDATE BY NAME
+----
+balance