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。
The most common example of this performance issue is the join operation.
这种性能问题的最常见的例子是连接(join)操作。
To achieve our common goal, let us join hands to create brilliant!
为了我们共同的目标，让我们携手共进、共创辉煌！
To achieve our common goal, let us join hands to create brilliant!
为了我们共同的目标，让我们携手共进、共创辉煌！
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