Syntax Error on ALTER TABLE with USING Clause in pg-mem

[jamesvillarrubia]

Describe the bug

When attempting to alter a table column type with a USING clause, pg-mem throws a syntax error. This operation is supported by PostgreSQL but seems to be either unimplemented or incorrectly handled in pg-mem. This would be helpful for migration testing.

To Reproduce

To reproduce the issue, you can run the following SQL command on the pg-mem playground:

CREATE TABLE chunks (userId text);
ALTER TABLE "chunks" ALTER COLUMN "userId" TYPE integer USING ("userId"::integer);

This command should convert the userId column from text to integer using a cast, but it fails in pg-mem while it succeeds in an actual PostgreSQL database.

pg-mem version

3.0.4