CREATE TABLE test(i INTEGER, j TIMESTAMP TIME INDEX);

Affected Rows: 0

INSERT INTO test VALUES (1, 1), (2, 2);

Affected Rows: 2

ALTER TABLE test DROP COLUMN "I";

Error: 4002(TableColumnNotFound), Column I not exists in table test

ALTER TABLE test DROP COLUMN I;

Affected Rows: 0

SELECT * FROM test;

+-------------------------+
| j                       |
+-------------------------+
| 1970-01-01T00:00:00.001 |
| 1970-01-01T00:00:00.002 |
+-------------------------+

ALTER TABLE test DROP COLUMN j;

Error: 1004(InvalidArguments), Not allowed to remove index column j from table test

DROP TABLE test;

Affected Rows: 0