Join works only if the files being joined share a common field.

join只有在所要连接的文件共享某个共同的域时才会工作。

youdao

As of this writing, YQL doesn't allow you to link tables through common keys (a join), but only permits you to use the results of one query inside another (a subquery).

在撰写本文时，YQL还不允许您通过公用键(一个联接)来链接表，只允许您在一个查询(一个子查询)内使用另一个查询的结果。

youdao

The participating leaders spoke highly of the achievements made by East Asian cooperation, vowing to join hands to achieve common prosperity and create a brighter future for regional cooperation.

与会各国领导人积极评价东亚合作取得的进展，表示愿携手合作，实现共同繁荣，开创东亚区域合作的美好未来。

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Is it possible for us to join hands in common effort?

VOA: special.2009.06.05

What used to be unorthodox career paths are becoming more and more common: many join the startup fever and launch their own ventures.

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The committee has suggested that it should only be optional for a two year transitional period, becoming compulsory thereafter for large cross-border companies, with small businesses being forced to join a common system after a further five years.

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However, the problem say the bankers is that in the absence of some kind of entente between the banking class and political class, the banks continue to feel discombobulated, and that makes it harder for them to join the common struggle to rebuild our economy (bankers, of course, say this more in sorrow, rather than as a threat).

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