Impala中的多个计数差异

Question

我需要找出给定时间段内不同患者数量之间的差异。

桌子是镶木地板的黑斑羚。

是否有更好的方式编写此查询。两个选择查询都使用同一张表。

在给定的时间范围内，只需对患者计数一次

WITH
 curr_prod AS 
(
    SELECT    product 
             ,COUNT(DISTINCT(patient_id)) AS rawPatientCount 
    FROM      tbl 
    WHERE     time_seq_id IN (12,11,10) 
    GROUP BY  product
)
,prev_prod AS 
(
    SELECT   product
            ,COUNT(DISTINCT(patient_id)) AS rawPatientCount 
    FROM     tbl 
    WHERE    time_seq_id in (7,8,9) 
    GROUP BY product
)
SELECT       COALESCE(curr_prod.product,prev_prod.product) AS product,
            ,curr_prod.rawPatientCount-prev_prod.rawPatientcount AS change_pat_cnt
FROM         curr_prod 
FULL OUTER JOIN prev_prod ON curr_prod.product=prev_prod.product