Issue type:

[ ] question
[x] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[x] mysql / mariadb
[ ] oracle
[ ] postgres
[ ] cockroachdb
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ ] latest
[ ] @next
[x] 0.2.17

Steps to reproduce or a small repository showing the problem:

I was renaming a createdAt column created by @CreateDateColumn() from created_at to createdAt using this migration.

await queryRunner.renameColumn('some_entity', 'created_at', 'createdAt');

This resulted in the following SQL query and error:

ALTER TABLE `some_entity` CHANGE `created_at` `createdAt` datetime(6) NOT NULL DEFAULT 'current_timestamp(6)'

QueryFailedError: ER_TRUNCATED_WRONG_VALUE: Incorrect datetime value: 'current_timestamp(6)' for column ``.``.`createdAt` at row 1

I think that TypeORM is reading the default value and using it when renaming the column, but not understanding that the current_timestamp(6) coming from the database is not a string but TypeORM is passing a string back to the database.

This happens no matter what form of renameColumn or changeColumn I use since renameColumn just defers to changeColumn and changeColumn decides whether to change or rename based on whether the TableColumn data you pass in is different.