should be it

external/duckdb/test/sql/alter/drop_col/test_drop_col.test

@@ -0,0 +1,19 @@
+# name: test/sql/alter/drop_col/test_drop_col.test
+# description: Test ALTER TABLE DROP COLUMN: standard drop column
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+statement ok
+ALTER TABLE test DROP COLUMN j
+
+query I
+SELECT * FROM test
+----
+1
+2
+

external/duckdb/test/sql/alter/drop_col/test_drop_col_check.test

@@ -0,0 +1,49 @@
+# name: test/sql/alter/drop_col/test_drop_col_check.test
+# description: Test ALTER TABLE DROP COLUMN: DROP COLUMN with check constraint
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER CHECK(j < 10))
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+query II
+SELECT * FROM test
+----
+1
+1
+2
+2
+
+statement ok
+ALTER TABLE test DROP COLUMN j
+
+statement ok
+INSERT INTO test VALUES (3)
+
+query I
+SELECT * FROM test
+----
+1
+2
+3
+
+statement ok
+CREATE TABLE test2(i INTEGER, j INTEGER CHECK(i+j < 10))
+
+statement ok
+INSERT INTO test2 VALUES (1, 1), (2, 2)
+
+query II
+SELECT * FROM test2
+----
+1
+1
+2
+2
+
+statement error
+ALTER TABLE test2 DROP COLUMN j
+----
+Catalog Error: Cannot drop column "j"

external/duckdb/test/sql/alter/drop_col/test_drop_col_check_next.test

@@ -0,0 +1,35 @@
+# name: test/sql/alter/drop_col/test_drop_col_check_next.test
+# description: Test ALTER TABLE DROP COLUMN: DROP COLUMN with check constraint on subsequent column
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER CHECK(j < 10))
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+query II
+SELECT * FROM test
+----
+1
+1
+2
+2
+
+statement ok
+ALTER TABLE test DROP COLUMN i
+
+statement error
+INSERT INTO test VALUES (20)
+----
+
+statement ok
+INSERT INTO test VALUES (3)
+
+query I
+SELECT * FROM test
+----
+1
+2
+3
+

external/duckdb/test/sql/alter/drop_col/test_drop_col_failure.test

@@ -0,0 +1,28 @@
+# name: test/sql/alter/drop_col/test_drop_col_failure.test
+# description: Test ALTER TABLE DROP COLUMN: Incorrect DROP COLUMN usage
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+# cannot drop column which does not exist
+statement error
+ALTER TABLE test DROP COLUMN blabla
+----
+Binder Error: Table "test" does not have a column with name "blabla"
+
+# unless IF EXISTS is specified
+statement ok
+ALTER TABLE test DROP COLUMN IF EXISTS blabla
+
+#  cannot drop ALL columns of a table
+statement ok
+ALTER TABLE test DROP COLUMN i
+
+statement error
+ALTER TABLE test DROP COLUMN j
+----
+Catalog Error: Cannot drop column: table only has one column remaining

external/duckdb/test/sql/alter/drop_col/test_drop_col_index.test

@@ -0,0 +1,24 @@
+# name: test/sql/alter/drop_col/test_drop_col_index.test
+# description: Test ALTER TABLE DROP COLUMN: DROP COLUMN with index built on subsequent column
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+statement ok
+CREATE INDEX i_index ON test(j)
+
+# cannot drop indexed column
+statement error
+ALTER TABLE test DROP COLUMN j
+----
+Catalog Error: Cannot drop this column: an index depends on it
+
+# we also cannot drop the column i (for now) because an index depends on a subsequent column
+statement error
+ALTER TABLE test DROP COLUMN i
+----
+Catalog Error: Cannot drop this column: an index depends on a column

external/duckdb/test/sql/alter/drop_col/test_drop_col_not_null.test

@@ -0,0 +1,31 @@
+# name: test/sql/alter/drop_col/test_drop_col_not_null.test
+# description: Test ALTER TABLE DROP COLUMN: DROP COLUMN with NOT NULL constraint
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER NOT NULL)
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+query II
+SELECT * FROM test
+----
+1
+1
+2
+2
+
+statement ok
+ALTER TABLE test DROP COLUMN j
+
+statement ok
+INSERT INTO test VALUES (3)
+
+query I
+SELECT * FROM test
+----
+1
+2
+3
+

external/duckdb/test/sql/alter/drop_col/test_drop_col_not_null_next.test

@@ -0,0 +1,40 @@
+# name: test/sql/alter/drop_col/test_drop_col_not_null_next.test
+# description: Test ALTER TABLE DROP COLUMN: DROP COLUMN with NOT NULL constraint on subsequent column
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER, k INTEGER NOT NULL)
+
+statement ok
+INSERT INTO test VALUES (1, 1, 11), (2, 2, 12)
+
+query III
+SELECT * FROM test
+----
+1
+1
+11
+2
+2
+12
+
+statement ok
+ALTER TABLE test DROP COLUMN j
+
+statement error
+INSERT INTO test VALUES (3, NULL)
+----
+
+statement ok
+INSERT INTO test VALUES (3, 13)
+
+query II
+SELECT * FROM test
+----
+1
+11
+2
+12
+3
+13
+

external/duckdb/test/sql/alter/drop_col/test_drop_col_operations.test

@@ -0,0 +1,28 @@
+# name: test/sql/alter/drop_col/test_drop_col_operations.test
+# description: Test various operations on a table after dropping a column
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok
+INSERT INTO test SELECT i, i FROM range(100) tbl(i);
+
+statement ok
+ALTER TABLE test DROP COLUMN i
+
+statement ok
+DELETE FROM test WHERE j%2=0
+
+query II
+SELECT COUNT(j), SUM(j) FROM test
+----
+50	2500
+
+statement ok
+UPDATE test SET j=j+100
+
+query II
+SELECT COUNT(j), SUM(j) FROM test
+----
+50	7500

external/duckdb/test/sql/alter/drop_col/test_drop_col_pk.test

@@ -0,0 +1,29 @@
+# name: test/sql/alter/drop_col/test_drop_col_pk.test
+# description: Test ALTER TABLE DROP COLUMN: DROP COLUMN from table with primary key constraint
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER PRIMARY KEY, j INTEGER)
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+# cannot drop primary key column
+statement error
+ALTER TABLE test DROP COLUMN i
+----
+
+# but we can drop column "j"
+statement ok
+ALTER TABLE test DROP COLUMN j
+
+statement ok
+INSERT INTO test VALUES (3)
+
+query I
+SELECT * FROM test
+----
+1
+2
+3
+

external/duckdb/test/sql/alter/drop_col/test_drop_col_rollback.test

@@ -0,0 +1,33 @@
+# name: test/sql/alter/drop_col/test_drop_col_rollback.test
+# description: Test ALTER TABLE DROP COLUMN: Rollback of DROP COLUMN
+# group: [drop_col]
+
+statement ok
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+statement ok
+BEGIN TRANSACTION
+
+statement ok
+ALTER TABLE test DROP COLUMN j
+
+query I
+SELECT * FROM test
+----
+1
+2
+
+statement ok
+ROLLBACK
+
+query II
+SELECT * FROM test
+----
+1
+1
+2
+2
+

external/duckdb/test/sql/alter/drop_col/test_drop_col_transactions.test

@@ -0,0 +1,144 @@
+# name: test/sql/alter/drop_col/test_drop_col_transactions.test
+# description: Test ALTER TABLE DROP COLUMN with multiple transactions
+# group: [drop_col]
+
+statement ok con1
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok con1
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+# Only one pending table alter can be active at a time
+statement ok con1
+BEGIN TRANSACTION
+
+# con removes a column to test
+statement ok con1
+ALTER TABLE test DROP COLUMN j
+
+# con2 cannot add a new column now!
+statement error con2
+ALTER TABLE test ADD COLUMN k INTEGER
+----
+TransactionContext Error: Catalog write-write conflict
+
+statement ok con1
+COMMIT
+
+# we can add the column after the commit
+statement ok con2
+ALTER TABLE test ADD COLUMN k INTEGER
+
+statement ok con1
+DROP TABLE test
+
+statement ok con1
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok con1
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+# Can only append to newest table
+statement ok con1
+BEGIN TRANSACTION
+
+# con removes a column from test
+statement ok con1
+ALTER TABLE test DROP COLUMN i
+
+# con2 cannot append now!
+statement error con2
+INSERT INTO test (i, j) VALUES (3, 3)
+----
+<REGEX>:.*TransactionContext Error: Transaction conflict.*altered by a different transaction.*
+
+# nor delete
+statement error con2
+DELETE FROM test WHERE i=1
+----
+<REGEX>:.*TransactionContext Error: Failed to commit.*another transaction has altered this table.*
+
+query I con1
+SELECT * FROM test
+----
+1
+2
+
+query II con2
+SELECT * FROM test
+----
+1	1
+2	2
+
+# we can't update on tables that have been altered
+statement error con2
+UPDATE test SET j=100
+----
+<REGEX>:.*TransactionContext Error: Transaction conflict.*altered by a different transaction.*
+
+query I con1
+SELECT * FROM test
+----
+1
+2
+
+statement ok con1
+UPDATE test SET j=100
+
+statement ok con1
+COMMIT
+
+query I con1
+SELECT * FROM test
+----
+100
+100
+
+statement ok con1
+DROP TABLE test
+
+statement ok con1
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok con1
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+# Alter table while other transaction still has pending appends
+statement ok con2
+BEGIN TRANSACTION
+
+statement ok con2
+INSERT INTO test VALUES (3, 3)
+
+# now con adds a column
+statement ok con1
+ALTER TABLE test DROP COLUMN i
+
+# cannot commit con2! conflict on append
+statement error con2
+COMMIT
+----
+<REGEX>:.*TransactionContext Error: Failed to commit.*altered by a different transaction.*
+
+statement ok con1
+DROP TABLE test
+
+statement ok con1
+CREATE TABLE test(i INTEGER, j INTEGER)
+
+statement ok con1
+INSERT INTO test VALUES (1, 1), (2, 2)
+
+# Create index on column that has been removed by other transaction
+# con2 removes a column
+statement ok con2
+BEGIN TRANSACTION
+
+statement ok con2
+ALTER TABLE test DROP COLUMN j
+
+# now con tries to add an index to that column: this should fail
+statement error con1
+CREATE INDEX i_index ON test(j)
+----
+<REGEX>:.*TransactionContext Error: Transaction conflict: cannot add an index.*

external/duckdb/test/sql/alter/drop_col/test_drop_col_with_generated_cols.test

@@ -0,0 +1,18 @@
+# name: test/sql/alter/drop_col/test_drop_col_with_generated_cols.test
+# description: Test ALTER TABLE DROP COLUMN with generated cols in the table
+# group: [drop_col]
+
+statement ok
+create table t(i int, j as (2), k int, m as (3), n int);
+
+statement ok
+alter table t drop column n;
+
+statement ok
+alter table t drop column m;
+
+statement ok
+alter table t drop column k;
+
+statement ok
+alter table t drop column j;