将日期范围透视为多行

Question

我有一个 table T 这种格式：

ClientName	StartMonth	EndingMonth
X	Dec 2018	Jan 2021

我希望我的查询输出为：

ClientName	MonthRange	Year #
X	Dec 2018-Nov 2019	1
X	Dec 2019-Nov 2020	2
X	Dec 2020-Nov 2021	3

谁能帮我解决这个问题的最佳方法是什么？

Answer 1

试试这个：

WITH
indata(clientname,startmonth,endmonth) AS(
  SELECT 'x',DATE '2018-12-01', DATE '2021-01-01'
)
,
-- a series of at least 3 integers - no other way ...
y(y) AS (
          SELECT 1
UNION ALL SELECT 2
UNION ALL SELECT 3
UNION ALL SELECT 4
)
SELECT 
  clientname
,  TO_CHAR(ADD_MONTHS(startmonth,(y-1)*12),'Mon-YYYY')
 ||'-'
 ||TO_CHAR(ADD_MONTHS(startmonth,(y-1)*12+11),'Mon-YYYY') AS monthrange
, y AS "year#"
FROM indata CROSS JOIN y
WHERE ADD_MONTHS(startmonth,(y-1)*12) <= endmonth
ORDER BY y;

clientname|monthrange       |year#
x         |Dec-2018-Nov-2019|    1
x         |Dec-2019-Nov-2020|    2
x         |Dec-2020-Nov-2021|    3

将日期范围透视为多行

Pivot a Date Range into multiple rows

sql

pivot

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