hive中的OVER从句
1、使用标准的聚合函数COUNT、SUM、MIN、MAX、AVG
2、使用PARTITION BY语句,使用一个或者多个原始数据类型的列
3、使用PARTITION BY与ORDER BY语句,使用一个或者多个数据类型的分区或者排序列
4、使用窗口规范,窗口规范支持以下格式:
(ROWS | RANGE) BETWEEN (UNBOUNDED | [num]) PRECEDING AND ([num] PRECEDING | CURRENT ROW | (UNBOUNDED | [num]) FOLLOWING)
(ROWS | RANGE) BETWEEN CURRENT ROW AND (CURRENT ROW | (UNBOUNDED | [num]) FOLLOWING)
(ROWS | RANGE) BETWEEN [num] FOLLOWING AND (UNBOUNDED | [num]) FOLLOWING123
当ORDER BY后面缺少窗口从句条件,窗口规范默认是 RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW.