should be it

external/duckdb/test/sql/alter/list/add_column_in_struct.test

@@ -0,0 +1,67 @@
+# name: test/sql/alter/list/add_column_in_struct.test
+# description: Test adding fields to a STRUCT.
+# group: [list]
+
+query I
+WITH cte AS (
+	SELECT a::STRUCT(i INTEGER, j INTEGER)[] a FROM
+	VALUES ([ROW(1, 1)]), ([ROW(2, 2)]) t(a)
+)
+SELECT remap_struct(
+	a,
+	NULL::STRUCT(i INTEGER, j INTEGER, k INTEGER)[],
+	{'list': ('list', {'i': 'i', 'j': 'j'})},
+	{'list': {'k': NULL::INTEGER}}
+) FROM cte;
+----
+[{'i': 1, 'j': 1, 'k': NULL}]
+[{'i': 2, 'j': 2, 'k': NULL}]
+
+
+statement ok
+CREATE TABLE test(s STRUCT(i INTEGER, j INTEGER)[])
+
+statement ok
+INSERT INTO test VALUES ([ROW(1, 1)]), ([ROW(2, 2)])
+
+# Add a field to a STRUCT.
+
+statement ok
+ALTER TABLE test ADD COLUMN s.element.k INTEGER
+
+query I
+SELECT * FROM test;
+----
+[{'i': 1, 'j': 1, 'k': NULL}]
+[{'i': 2, 'j': 2, 'k': NULL}]
+
+statement ok
+DROP TABLE test;
+
+statement ok
+CREATE TABLE test(
+	s STRUCT(
+		a STRUCT(i INTEGER, j INTEGER)[]
+	)
+)
+
+statement ok
+INSERT INTO test VALUES (ROW([ROW(1, 1)])), (ROW([ROW(2, 2)]))
+
+# Add another (one more nesting level) STRUCT field.
+
+statement ok
+ALTER TABLE test ADD COLUMN s.a.element.k INTEGER
+
+query I
+SELECT * FROM test;
+----
+{'a': [{'i': 1, 'j': 1, 'k': NULL}]}
+{'a': [{'i': 2, 'j': 2, 'k': NULL}]}
+
+# Try to add an element to the list.
+
+statement error
+ALTER TABLE test ADD COLUMN s.a.not_element INTEGER
+----
+<REGEX>:Binder Error.*Column a is not a struct - ALTER TABLE can only add fields to structs.*

external/duckdb/test/sql/alter/list/drop_column_in_struct.test

@@ -0,0 +1,51 @@
+# name: test/sql/alter/list/drop_column_in_struct.test
+# description: Test dropping fields in a STRUCT.
+# group: [list]
+
+statement ok
+CREATE TABLE test(s STRUCT(i INTEGER, j INTEGER)[])
+
+statement ok
+INSERT INTO test VALUES ([ROW(1, 1)]), ([ROW(2, 2)])
+
+# Try to drop element from the list.
+
+statement error
+ALTER TABLE test DROP COLUMN s.element
+----
+<REGEX>:Catalog Error.*Cannot drop field.*not a struct.*
+
+# Now drop a STRUCT field.
+
+statement ok
+ALTER TABLE test DROP COLUMN s.element.j
+
+query I
+SELECT * FROM test
+----
+[{'i': 1}]
+[{'i': 2}]
+
+statement ok
+DROP TABLE test;
+
+statement ok
+CREATE TABLE test(
+	s STRUCT(
+		a STRUCT(i INTEGER, j INTEGER)[]
+	)
+)
+
+statement ok
+INSERT INTO test VALUES (ROW([ROW(1, 1)])), (ROW([ROW(2, 2)]))
+
+# Drop another (one more nesting level) STRUCT field.
+
+statement ok
+ALTER TABLE test DROP COLUMN s.a.element.i
+
+query I
+SELECT * FROM test
+----
+{'a': [{'j': 1}]}
+{'a': [{'j': 2}]}

external/duckdb/test/sql/alter/list/rename_column_in_struct.test

@@ -0,0 +1,58 @@
+# name: test/sql/alter/list/rename_column_in_struct.test
+# group: [list]
+
+statement ok
+CREATE TABLE test(
+	s STRUCT(
+		i INTEGER,
+		j INTEGER
+	)[]
+)
+
+statement ok
+INSERT INTO test VALUES
+	([ROW(1, 1)]),
+	([ROW(2, 2)])
+
+# attempt to rename 'element' from the list
+statement error
+ALTER TABLE test RENAME COLUMN s.element TO not_element
+----
+Catalog Error: Cannot rename field 'element' from column 's' - can only rename fields inside a struct
+
+statement ok
+ALTER TABLE test RENAME COLUMN s.element.j TO k
+
+query I
+select * from test
+----
+[{'i': 1, 'k': 1}]
+[{'i': 2, 'k': 2}]
+
+statement ok
+drop table test;
+
+statement ok
+CREATE TABLE test(
+	s STRUCT(
+		a STRUCT(
+			i INTEGER,
+			j INTEGER
+		)[]
+	)
+)
+
+statement ok
+INSERT INTO test VALUES
+	(ROW([ROW(1, 1)])),
+	(ROW([ROW(2, 2)]))
+
+# add a column to a struct
+statement ok
+ALTER TABLE test RENAME COLUMN s.a.element.i TO k
+
+query I
+select * from test
+----
+{'a': [{'k': 1, 'j': 1}]}
+{'a': [{'k': 2, 'j': 2}]}