本文介绍了Hive 中的 COLLECT_SET(),保留重复项?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有没有办法将重复项保留在 Hive 中的收集集中,或者使用其他方法模拟 Hive 提供的那种聚合集合?我想将列中具有相同键的所有项目聚合到一个数组中,并带有重复项.
Is there a way to keep the duplicates in a collected set in Hive, or simulate the sort of aggregate collection that Hive provides using some other method? I want to aggregate all of the items in a column that have the same key into an array, with duplicates.
即:
hash_id | num_of_cats ===================== ad3jkfk 4 ad3jkfk 4 ad3jkfk 2 fkjh43f 1 fkjh43f 8 fkjh43f 8 rjkhd93 7 rjkhd93 4 rjkhd93 7应该返回:
hash_agg | cats_aggregate =========================== ad3jkfk Array<int>(4,4,2) fkjh43f Array<int>(1,8,8) rjkhd93 Array<int>(7,4,7) 推荐答案Hive 0.13.0 后尝试使用 COLLECT_LIST(col)
Try to use COLLECT_LIST(col) after Hive 0.13.0
SELECT hash_id, COLLECT_LIST(num_of_cats) AS aggr_set FROM tablename WHERE blablabla GROUP BY hash_id ;更多推荐
Hive 中的 COLLECT
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