题目中给出了四张表：
图中S代表供货商，P代表商品，J代表商业项目，SP代表三者的联系（和这道小题暂时无关），现在需要在同一列显示出供货商、商品、商业项目所在的所有城市（city项）且不重复显示，请问有什么方法可以实现。。。。。
The connection between your three people must be related to this question. Otherwise, you cannot combine the three unrelated tables. But your three-way connection table is a bit messy. Is there no rule?
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The connection between your three people must be related to this question. Otherwise, you cannot combine the three unrelated tables. But your three-way connection table is a bit messy. Is there no rule?