查找两个日期时间段之间的重叠天数
我有两个表，每个表都保存日期的时间段(从 date1 到 date2)
I have two tables, each of which holds the period of dates (from date1 to date2)
我将在表 1 和表 2 中查找两个日期时间段之间重叠的天数
i will Find overlapping days between two periods of Date in table1 and table2
示例
table1
-------------------------
id | FromDate | ToDate
1 |2000-01-01 | 2000-02-04
2 |2000-03-01 | 2000-03-29
table2
-------------------------
id | FromDate | ToDate
1 |2000-02-01 | 2000-02-07
2 |2000-03-27 | 2000-03-29
我想要的结果:
2000-02-01
2000-02-02
2000-02-03
2000-02-04
2000-03-27
2000-03-28
2000-03-29
推荐答案
使用 CTE 和递归可以做到这一点.
It's possible to do this with CTE's and recursion.
--Your sample data
DECLARE @table1 TABLE (id int PRIMARY KEY, FromDate date, ToDate date)
DECLARE @table2 TABLE (id int PRIMARY KEY, FromDate date, ToDate date)
INSERT INTO @table1 VALUES (1, '2000-01-01', '2000-02-04') , (2, '2000-03-01', '2000-03-29')
INSERT INTO @table2 VALUES (1, '2000-02-01', '2000-02-07') , (2, '2000-03-27', '2000-03-29')
--A couple CTE's
;WITH cteDates AS (
SELECT T1.id --get the min and max dates for each id
,CASE WHEN T1.FromDate > T2.FromDate THEN T1.FromDate ELSE T2.FromDate END [mindate]
,CASE WHEN T1.ToDate < T2.ToDate THEN T1.ToDate ELSE T2.ToDate END [maxdate]
FROM @table1 T1 INNER JOIN @table2 T2 ON T1.id = T2.id
)
, cteRecursion AS ( --date range for each id
SELECT id, mindate AS DateValue
FROM cteDates
UNION ALL
SELECT id, DATEADD(DAY, 1, DateValue)
FROM cteRecursion C1
WHERE DATEADD(DAY, 1, DateValue) <= (
SELECT maxDate
FROM cteDates C2
WHERE C2.id = C1.id
)
)
--SELECT query
SELECT DateValue FROM cteRecursion ORDER BY DateValue OPTION (MAXRECURSION 0)
产生输出:
DateValue
---------
2000-02-01
2000-02-02
2000-02-03
2000-02-04
2000-03-27
2000-03-28
2000-03-29
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