我正在根据员工工作的时间块做一些报告。在某些情况下，数据包含两个单独的记录，实际上是一个时间块。
这是该表的基本版本和一些示例记录：
EmployeeID
StartTime
EndTime
数据：
EmpID Start End
----------------------------
#1001 10:00 AM 12:00 PM
#1001 4:00 PM 5:30 PM
#1001 5:30 PM 8:00 PM
在示例中，最后两条记录在时间上是连续的。我想编写一个组合任何相邻记录的查询，因此结果集是这样的：
EmpID Start End
----------------------------
#1001 10:00 AM 12:00 PM
#1001 4:00 PM 8:00 PM
理想情况下，它还应该能够处理超过 2 个相邻记录，但这不是必需的。
本文为您的问题提供了很多可能的解决方案
这似乎是最直接的：
WITH StartTimes AS
(
SELECT DISTINCT username, starttime
FROM dbo.Sessions AS S1
WHERE NOT EXISTS
(SELECT * FROM dbo.Sessions AS S2
WHERE S2.username = S1.username
AND S2.starttime < S1.starttime
AND S2.endtime >= S1.starttime)
),
EndTimes AS
(
SELECT DISTINCT username, endtime
FROM dbo.Sessions AS S1
WHERE NOT EXISTS
(SELECT * FROM dbo.Sessions AS S2
WHERE S2.username = S1.username
AND S2.endtime > S1.endtime
AND S2.starttime <= S1.endtime)
)
SELECT username, starttime,
(SELECT MIN(endtime) FROM EndTimes AS E
WHERE E.username = S.username
AND endtime >= starttime) AS endtime
FROM StartTimes AS S;
如果这是严格关于相邻行（而不是重叠行），您可以尝试以下方法：
取消旋转时间戳。
只留下那些没有重复的。
将其余的转回，将 eachStart与直接跟随的End.
或者，在 Transact-SQL 中，如下所示：
WITH unpivoted AS (
SELECT
EmpID,
event,
dtime,
count = COUNT(*) OVER (PARTITION BY EmpID, dtime)
FROM atable
UNPIVOT (
dtime FOR event IN (StartTime, EndTime)
) u
)
, filtered AS (
SELECT
EmpID,
event,
dtime,
rowno = ROW_NUMBER() OVER (PARTITION BY EmpID, event ORDER BY dtime)
FROM unpivoted
WHERE count = 1
)
, pivoted AS (
SELECT
EmpID,
StartTime,
EndTime
FROM filtered
PIVOT (
MAX(dtime) FOR event IN (StartTime, EndTime)
) p
)
SELECT *
FROM pivoted
;
在 SQL Fiddle有这个查询的演示。
累积总和的 CTE：
DECLARE @t TABLE(EmpId INT, Start TIME, Finish TIME)
INSERT INTO @t (EmpId, Start, Finish)
VALUES
(1001, '10:00 AM', '12:00 PM'),
(1001, '4:00 PM', '5:30 PM'),
(1001, '5:30 PM', '8:00 PM')
;WITH rowind AS (
SELECT EmpId, Start, Finish,
-- IIF returns 1 for each row that should generate a new row in the final result
IIF(Start = LAG(Finish, 1) OVER(PARTITION BY EmpId ORDER BY Start), 0, 1) newrow
FROM @t),
groups AS (
SELECT EmpId, Start, Finish,
-- Cumulative sum
SUM(newrow) OVER(PARTITION BY EmpId ORDER BY Start) csum
FROM rowind)
SELECT
EmpId,
MIN(Start) Start,
MAX(Finish) Finish
FROM groups
GROUP BY EmpId, csum
我已经更改了一些名称和类型以使示例更小，但这可以工作并且应该非常快并且它没有记录数限制：
with cte as (
select
x1.id
,x1.t1
,x1.t2
,case when x2.t1 is null then 1 else 0 end as bef
,case when x3.t1 is null then 1 else 0 end as aft
from x x1
left join x x2 on x1.id=x2.id and x1.t1=x2.t2
left join x x3 on x1.id=x3.id and x1.t2=x3.t1
where x2.id is null
or x3.id is null
)
select
cteo.id
,cteo.t1
,isnull(z.t2,cteo.t2) as t2
from cte cteo
outer apply (select top 1 *
from cte ctei
where cteo.id=ctei.id and cteo.aft=0 and ctei.t1>cteo.t1
order by t1) z
where cteo.bef=1
具有内联用户定义函数和 CTE 的选项
CREATE FUNCTION dbo.Overlap
(
@availStart datetime,
@availEnd datetime,
@availStart2 datetime,
@availEnd2 datetime
)
RETURNS TABLE
RETURN
SELECT CASE WHEN @availStart > @availEnd2 OR @availEnd < @availStart2
THEN @availStart ELSE
CASE WHEN @availStart > @availStart2 THEN @availStart2 ELSE @availStart END
END AS availStart,
CASE WHEN @availStart > @availEnd2 OR @availEnd < @availStart2
THEN @availEnd ELSE
CASE WHEN @availEnd > @availEnd2 THEN @availEnd ELSE @availEnd2 END
END AS availEnd
;WITH cte AS
(
SELECT EmpID, Start, [End], ROW_NUMBER() OVER (PARTITION BY EmpID ORDER BY Start) AS Id
FROM dbo.TableName
), cte2 AS
(
SELECT Id, EmpID, Start, [End]
FROM cte
WHERE Id = 1
UNION ALL
SELECT c.Id, c.EmpID, o.availStart, o.availEnd
FROM cte c JOIN cte2 ct ON c.Id = ct.Id + 1
CROSS APPLY dbo.Overlap(c.Start, c.[End], ct.Start, ct.[End]) AS o
)
SELECT EmpID, Start, MAX([End])
FROM cte2
GROUP BY EmpID, Start
SQLFiddle上的演示