Sql 每周为每位客户获取最新记录

我试图查询一个表并返回按周分组的客户选择的最新组合。例如，以下是表格：

(int)        (string)    (int)      (bigint)
Customer ID  Choice      Week       Inserted at
100          a, b, c     2      20171002
100          a, b        2      20171004
101          b, c, d     2      20171002
102          a, c, d     2      20171002
103          a, b, c     2      20171002
103          a, b, d     2      20171003
100          a, b, c, d  3      20171010
101          a, c, d     3      20171010
101          b, c, d     3      20171011
102          a, b        3      20171010
103          a, b, c     3      20171010
103          b, c, d     3      20171012
103          a, b, d     3      20171014

这就是我想提出的问题：

Customer ID  Choice         Week    Inserted at
100          a, b           2       20171004
101          b, c, d        2       20171002
102          a, c, d        2       20171002
103          a, b, d        2       20171003
100          a, b, c, d     3       20171010
101          b, c, d        3       20171011
102          a, b           3       20171010
103          a, b, d        3       20171014

客户每天只能对其选择进行一次更改，因此我不必担心客户在一天内进行多次更改

这是我开始的内容，但它缺少很多行。有什么反馈吗

SELECT c.customer, c.combo, c.week, c.date
FROM tableCombos AS c
WHERE not exists (SELECT *
                  FROM tableCombos AS recent
                  WHERE recent.customer = c.customer
                  AND recent.date > c.date)

使用窗口功能：

select tc.*
from (select tc.*,
             row_number() over (partition by customer, week order by date desc) as seqnum
      from tableCombos tc
     ) tc
where seqnum = 1;

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首先，我希望获得按周和客户分组的最大o日期：

select customerId , week, max(insertedAt) as date
group by customerId , WEEK

之后，我可以将这个数据集与主表连接起来

SELECT c.customer, c.combo, c.week, c.date
FROM tableCombos AS c
join (select customerId , week, max(insertedAt) as date
group by customerId , WEEK) X 
on c.customerId = X.customerId 
                  and c.week = X.week 
                  and c.date = X.date 

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你在使用哪种RDBMS？我在Cloudera Impala工作