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请问SparkSQL中先union再join，会比先join再union更高效吗？ #28

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ycli12 opened this issue Mar 8, 2022 · 0 comments

ycli12 commented Mar 8, 2022

假如有A、B、C三个表，下面两种操作 (A union B) join C 会比 (A join C) union (B join C) 更快吗？考虑到网络IO和Hash Join等操作的情况下。

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