Amazon Redshift机制，用于将列聚合为字符串[重复]

受Masashi启发，此解决方案更简单，并且可以从Redshift中从一组中选择一个随机元素。

SELECt id, first_value as attribute FROM(SELECt id, FIRST_VALUE(attribute)     OVER(PARTITION BY id ORDER BY random()     ROWS BETWEEN unbounded preceding AND unbounded following)     FROM dataset) GROUP BY id, attribute ORDER BY id;