对多个输入SchemaPCollection,根据指定的字段(dict)对SchemaPCollection做内连接操作, 连接结果为(fields, (value1, value2, ..., value n)), 若第m个SchemaPCollection没有元素, 则value m为None Args: *pcollection (SchemaPCollection): 输入的多个SchemaPCollection **options: 配置选项,需要配置fields=str/tuple/list(一个列表、元组、一个逗
(*pcollections, **options)
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