值得注意的是，您在执行其他查询函数时不能在指针和结果集上执行distinct函数，而应直接在集合上执行。
It's worth noting that you do not perform the distinct function on a cursor or result set as you do other query functions, but you perform it directly on the collection.
证明了一个有关集合交的可加集函数关系式，并结合上述结果证明了测度论中的一个重要的可加集函数关系式。
An expression of additive set function is given, and another important related expression of additive set function in measure theory is also presented.
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