To be hohnest, only the last 2 Oracle question sounds resaonable.
I do not really imagine of what importance is to know how to change the SQL promt?
Not to mention that the answer of the duplicate rows question is not really correct, since it supposes that DUPLICATE means strictly 2 identical rows, no more.I am also not completely sure what the second solution to that question would do, but I would not sign that only the duplicated rows will be deleted.