I've encountered what appears (to me) to be buggy behavior when using the ALTER TABLE ADD IF NOT EXISTS functionality to conditionally add columns, and just wanted to check off that it is (or isn't) actually a bug.
If I have a table and execute an "ALTER TABLE ADD IF NOT EXISTS thisColAlreadyExists varchar, thisColDoesNotExist varchar", then nothing will be changed in the table because thisColAlreadyExists already exists. If I omit the already-existing column from the statement, all columns do get created. My expectation would be that when you use ADD IF NOT EXISTS, all non-existent columns will be added, and all existing columns in the statement will just be ignored. I've noticed that there is a test (AlterTableIT#testAddVarCols) that actually demonstrates the current behavior, which makes me think that it must be intentional and not a bug -- however, I'd just like to check. Can anyone enlighten me? Thanks, Gabriel
