如何在 Oracle 中的两个日期 ID 之间获取每月计数

Question

我想获取两个日期范围之间的每月计数。例如，让我们采用以下范围：

20181202 - 20190202

此范围将为 2018 年的“十二月”和 2019 年的“一月”、“二月”的计数提供 +1。

目前我按月和年汇总以获得这些计数，但我忘记了日期之间存在超过 1 年差距的情况。

查询现在看起来像这样：

    CREATE VIEW V_A_A AS
SELECT CASE WHEN 01>=JT.SUBSTR(START,5,2) AND 01<=JT.SUBSTR(ENDID,1,4) THEN 'JAN'
WHEN 02>=JT.SUBSTR(START,5,2) AND 02<=JT.SUBSTR(ENDID,5,2) THEN 'FEB'
WHEN 03>=JT.SUBSTR(START,5,2) AND 03<=JT.SUBSTR(ENDID,5,2) THEN 'MAR'
WHEN 04>=JT.SUBSTR(START,5,2) AND 04<=JT.SUBSTR(ENDID,5,2) THEN 'APR'
WHEN 05>=JT.SUBSTR(START,5,2) AND 05<=JT.SUBSTR(ENDID,5,2) THEN 'MAY'
WHEN 06>=JT.SUBSTR(START,5,2) AND 06<=JT.SUBSTR(ENDID,5,2) THEN 'JUNE'
WHEN 07>=JT.SUBSTR(START,5,2) AND 07<=JT.SUBSTR(ENDID,5,2) THEN 'JULY'
WHEN 08>=JT.SUBSTR(START,5,2) AND 08<=JT.SUBSTR(ENDID,5,2) THEN 'AUG'
WHEN 09>=JT.SUBSTR(START,5,2) AND 09<=JT.SUBSTR(ENDID,5,2) THEN 'SEPT'
WHEN 10>=JT.SUBSTR(START,5,2) AND 10<=JT.SUBSTR(ENDID,5,2) THEN 'OCT'
WHEN 11>=JT.SUBSTR(START,5,2) AND 11<=JT.SUBSTR(ENDID,5,2) THEN 'NOV'
WHEN 12>=JT.SUBSTR(START,5,2) AND 12<=JT.SUBSTR(ENDID,5,2) THEN 'DEC' ELSE 'N/A' END MONTH
,CASE WHEN 2019>=JT.SUBSTR(START,1,4) AND 2019<=JT.SUBSTR(ENDID,1,4) THEN 2019 
WHEN 2018>=JT.SUBSTR(START,1,4) AND 2018<=JT.SUBSTR(ENDID,1,4) THEN 2018
WHEN 2017>=JT.SUBSTR(START,1,4) AND 2017<=JT.SUBSTR(ENDID,1,4) THEN 2017
WHEN 2016>=JT.SUBSTR(START,1,4) AND 2016<=JT.SUBSTR(ENDID,1,4) THEN 2016
WHEN 2015>=JT.SUBSTR(START,1,4) AND 2015<=JT.SUBSTR(ENDID,1,4) THEN 2015 ELSE 0 END YEAR
,COUNT(*) AS COUNT
from 
(select * from some_db a
INNER JOIN another_db b ON a.field = b.field
WHERE a.name = "Private" JT 
GROUP BY CASE WHEN 2019>=JT.SUBSTR(START,1,4) AND 2019<=JT.SUBSTR(ENDID,1,4) THEN 2019 
WHEN 2018>=JT.SUBSTR(START,1,4) AND 2018<=JT.SUBSTR(ENDID,1,4) THEN 2018
WHEN 2017>=JT.SUBSTR(START,1,4) AND 2017<=JT.SUBSTR(ENDID,1,4) THEN 2017
WHEN 2016>=JT.SUBSTR(START,1,4) AND 2016<=JT.SUBSTR(ENDID,1,4) THEN 2016
WHEN 2015>=JT.SUBSTR(START,1,4) AND 2015<=JT.SUBSTR(ENDID,1,4) THEN 2015 ELSE 0 END,
CASE WHEN 01>=JT.SUBSTR(START,5,2) AND 01<=JT.SUBSTR(ENDID,1,4) THEN 'JAN'
WHEN 02>=JT.SUBSTR(START,5,2) AND 02<=JT.SUBSTR(ENDID,5,2) THEN 'FEB'
WHEN 03>=JT.SUBSTR(START,5,2) AND 03<=JT.SUBSTR(ENDID,5,2) THEN 'MAR'
WHEN 04>=JT.SUBSTR(START,5,2) AND 04<=JT.SUBSTR(ENDID,5,2) THEN 'APR'
WHEN 05>=JT.SUBSTR(START,5,2) AND 05<=JT.SUBSTR(ENDID,5,2) THEN 'MAY'
WHEN 06>=JT.SUBSTR(START,5,2) AND 06<=JT.SUBSTR(ENDID,5,2) THEN 'JUNE'
WHEN 07>=JT.SUBSTR(START,5,2) AND 07<=JT.SUBSTR(ENDID,5,2) THEN 'JULY'
WHEN 08>=JT.SUBSTR(START,5,2) AND 08<=JT.SUBSTR(ENDID,5,2) THEN 'AUG'
WHEN 09>=JT.SUBSTR(START,5,2) AND 09<=JT.SUBSTR(ENDID,5,2) THEN 'SEPT'
WHEN 10>=JT.SUBSTR(START,5,2) AND 10<=JT.SUBSTR(ENDID,5,2) THEN 'OCT'
WHEN 11>=JT.SUBSTR(START,5,2) AND 11<=JT.SUBSTR(ENDID,5,2) THEN 'NOV'
WHEN 12>=JT.SUBSTR(START,5,2) AND 12<=JT.SUBSTR(ENDID,5,2) THEN 'DEC' ELSE 'N/A' END

Answer 1

据我了解，您需要整年的边界日期（在这种情况下为 2018 - 2019 年）。所以应该有24行。如果这 24 个月与边界日期之间的间隔月重合，那么您需要计数为 1，否则为 0。所以，考虑一下：

SELECT SUBSTR(t1.months,1,4) as "Year", 
       TO_CHAR( TO_DATE(t1.months,'yyyymm'), 'Month' ) as "Month",
       NVL2(t2.months,1,0) as "Count"
  FROM
  (
SELECT y.years||m.months as months
  FROM
  (
   SELECT DISTINCT TO_CHAR(ADD_MONTHS( TO_DATE('20181202','yyyymmdd') , level - 1 ),'yyyy')
          as years
     FROM dual
  CONNECT BY level <= 
    MONTHS_BETWEEN(TO_DATE('20190202','yyyymmdd'),TO_DATE('20181202','yyyymmdd')) + 1 ) y
   CROSS JOIN
   (
    SELECT LPAD(LEVEL,2,'0') months
      FROM dual
   CONNECT BY level <= 12
   ) m
  ) t1
 LEFT JOIN
 (
    SELECT TO_CHAR(ADD_MONTHS( TO_DATE('20181202','yyyymmdd') , level - 1 ),'yyyymm')
          as months
     FROM dual
  CONNECT BY level <= 
      MONTHS_BETWEEN(TO_DATE('20190202','yyyymmdd'),TO_DATE('20181202','yyyymmdd')) + 1
 ) t2
 ON t1.months = t2.months
 ORDER BY t1.months

CROSS JOIN 然后递归LEFT JOIN。

Demo