根据每年每季度最高序列号获取总金额

Question

考虑我们有这样一个表：

eid  report_year report_qurter seqnum quarter1_grossamt quarter2_grossamt
101  2015        1             0      20000.00          0.00
101  2015        1             1      3000              0.00
102  2016        1             0      40000             0.00
102  2016        1             2      6000              0.00
101  2015        2             0      0.00              20000

输出应该是：

eid   report_year    report_quarter         seqnum           grossamt
101   2015           1                      1                3000
102   2016           1                      2                6000            
101   2015           2                      0                20000           

记录应根据每季度的最大seqnum打印，并打印相关的总金额

Answer 1

SELECT eid , T.report_year ,  T.report_qurter ,   T.seqnum , CASE WHEN 
quarter1_grossamt <> 0 THEN quarter1_grossamt ELSE quarter2_grossamt END
FROM #Table T
JOIN
(
  SELECT report_year,report_qurter,MAX(seqnum) seqnum
  FROM #Table
  GROUP BY report_year,report_qurter
)A ON A.report_year = T.report_year AND T.report_qurter = A.report_qurter     
AND T.seqnum = A.seqnum 

Answer 2

一种方法是使用窗口函数查找每年和每季度最大序列号的记录。

SELECT t.eid,
       t.report_year,
       t.report_quarter,
       t.seqnum,
       t.grossamt
FROM
(
    SELECT eid,
           report_year,
           report_quarter,
           seqnum,
           MAX(seqnum) OVER(PARTITION BY report_year, report_quarter) maxSeqNum,
           CASE WHEN report_quarter = 1
                THEN quarter1_grossamt
                ELSE quarter2_grossamt END AS grossamt
    FROM yourTable
) t
WHERE t.seqnum = t.maxSeqNum