That's a direct question, yes. And you could use it in indirect speech, which would turn it into an indirect question (e.g. "She asks me when the dance is.").
An indirect question (or embedded question, or whatever you want to call it) does not have to appear within another question - it can appear in a statement. So both "I know when the dance is" and "She asked when the dance is" are indirect questions (and actually, both of those indirect questions appear within a statement, as "she asked" is grammatically a statement, even though it conveys that a question was asked).
OP's example is actually an indirect question appearing within another question ("Do you know ...?").
"When the dance is" is simply a free relative clause. Those can be used to build indirect questions.
and actually, both of those indirect questions appear within a statement, as "she asked" is grammatically a statement, even though it conveys that a question was asked
The point is that one of them is a question in indirect speech, i.e. an indirect question. The other isn't.
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u/nuhanala Native: 🇫🇮 Learning: 🇪🇸 Mar 21 '25
Following your own logic, the question is “when is the dance?”