SQLite

The DROP COLUMN statement below works, even though the column is indexed:

CREATE TABLE t1(a,b);
INSERT INTO t1 VALUES(1,2);
CREATE INDEX x1 on t1("b");
ALTER TABLE t1 DROP COLUMN b;

Subsequently reopening the database and running "PRAGMA integrity_check" reports index corruption. The "index corruption" problem can be resolved by dropping the (now superfluous) index, so this is perhaps not a serious concern, but it does need to be fixed.

The problem was reported by Forum post e37dcf456a. It is perhaps related to ticket [9b78184be266fd70].

A slightly different example of this problem that is not resolved by check-in 7c8aa3812599d58a.

CREATE TABLE t1(a, b, c);
CREATE UNIQUE INDEX x1 ON t1("a"||"b");
INSERT INTO t1 VALUES(1,2,3),(1,4,5);
ALTER TABLE t1 DROP COLUMN b;
PRAGMA integrity_check;