I found a question that was tagged by a user with
mysql was intended. Should I report this as an error somehow or is
If you're certain it was someone's typo, just remove it from the post, or suggest an edit to do so if you don't have editing privileges, and the tag will be automatically deleted after a set time (midnight UTC).
No flagging is necessary. If you have proposed an edit rather than editing directly, you could leave a brief comment to alert the OP to accept your edit, but that's also not really necessary as he/she will receive a notification that you've suggested an edit.