Tag Info  New answers tagged   We already have 154 questions
tagged relational division and probably many more on the same
concept that have not been tagged. There is no need to create
yet another QA pair. Just look at the top voted answers in the
tag. I'd personally go for this one as the answers show many
different ways to skin the cat. And perhaps edit the question to
make it more ...   Consider posting yourself a canonical
question using the description you gave here, as it is quite
synthetic and very clear: Consider this table: | student |
course | +---------+---------+ | Adam | Math | | Adam | Science
| | John | Math | | John | Science | | Jane | Math | | Jane |
Physics | I want to pull all students ...   Something I believe
individual users can do to prevent themselves from doing this
sort of thing is to offer a bounty. In my personal experience,
if I asked a question that got low views or an answer that
didn't help, I would offer a bounty on it (that is, if I felt I
really had asked a good question).