ORACLE Top/Bottom N、First/Last、NTile

目录
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1.带空值的排列
2.Top/Bottom N查询
3.First/Last排名查询
4.按层次查询
一、带空值的排列：
假如被排列的数据中含有空值呢？
SQL> select region_id, customer_id,
   2         sum(customer_sales) cust_sales,
   3         sum(sum(customer_sales)) over(partition by region_id) ran_total,
   4         rank() over(partition by region_id
   5                  order by sum(customer_sales) desc) rank
   6    from user_order
   7   group by region_id, customer_id;
REGION_ID CUSTOMER_ID CUST_SALES RAN_TOTAL       RANK
---------- ----------- ---------- ---------- ----------
         10          31               6238901          1
         10          26    1808949    6238901          2
         10          27    1322747    6238901          3
         10          30    1216858    6238901          4
         10          28