Question tags — “did you” vs. “didn’t you”
Which one is correct?
You have no idea, don't you?
or, option 2:
You have no idea, do you?
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The general principle is that when the main clause is positive, the question tag is negative. You have no idea is made negative by the presence of no. It follows that the tag will be do you?
In general "do you" since the first part of the sentence is negative (contains "no"). But sometimes natives use it wrongly "negative + negative" to highlight that situation is absolutely clear and there is no choice in the question.