MapReduce表连接操作之Map端join
https://blog.csdn.net/lzm1340458776/article/details/42971075
MapReduce表连接操作之Reduce端join
https://blog.csdn.net/lzm1340458776/article/details/42971485
MapReduce表连接之半连接SemiJoin
https://blog.csdn.net/lzm1340458776/article/details/43017425
原文：https://www.cnblogs.com/hdc520/p/11027083.html