Hive 的collect_set使用详解

有这么一需求，在hive中求出一个数据表中在某天内首次登录的人；能够借助collect_set来处理sql:html select count(a.id) from (select id,collect_set(time) as t from t_action_login where time<='20150906' group by id) as a where size(a.t)=1 and

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