例如，考虑一个跨三个数据源的联邦联合查询。

For example, consider a federated union query across three sources.

youdao

我应该使用连接或联合这个MySQL查询？

Should I use JOIN or UNION for this MYSQL query?

youdao

若有疑问，请致电联合船代或我司客服部门查询！

Any query, please feel free to contact Unisco or us, thank you!

youdao

若有疑问，请致电联合船代或我司客服部门查询！

Any query, please feel free to contact Unisco or us, thank you!

youdao