Joining massive CTE tables (13,000,000 rows+) performance problems - sql

Question

We have a production database that manages personnel booking at 100s of branches for years in advance with minute level accuracy.
Part of this system are reports that highlight gaps, i.e. compare branch opening hours and staff bookings to see if any branches are open with nobody booked.
It also checks for overlaps, double bookings etc all at the same time, basically minute level accuracy is required.
The way we're doing this is to expand the start and end times of openings hours and bookings into minutes with an integer tally table:
--===== Create and populate the Tally table on the fly
SELECT TOP 16777216
IDENTITY(INT,1,1) AS N
INTO dbo.Tally
FROM Master.dbo.SysColumns sc1,
Master.dbo.SysColumns sc2,
Master.dbo.SysColumns sc3
--===== Add a Primary Key to maximize performance
ALTER TABLE dbo.Tally
ADD CONSTRAINT PK_Tally_N
PRIMARY KEY CLUSTERED (N) WITH FILLFACTOR = 100
We utilise this static indexed tally table to expand opening hours and bookings as follows:
SELECT [BranchID] ,
[DayOfWeek] ,
DATEADD(MINUTE, N - 1, StartTime)
FROM OpeningHours
LEFT OUTER JOIN tally ON tally.N BETWEEN 0
AND DATEDIFF(MINUTE, OpeningHours.StartTime, OpeningHours.EndTime) + 1
The problem is, once we have the 13,000,000 "open minutes" and the "booked minutes" we then need to join the results to see what's covered:
SELECT OpenDatesAndMinutes.[Date] ,
OpenDatesAndMinutes.[Time] ,
OpenDatesAndMinutes.[BranchID] ,
ISNULL(BookedMinutes.BookingCount, 0) AS BookingCount
FROM OpenDatesAndMinutes
LEFT OUTER JOIN BookedMinutes ON OpenDatesAndMinutes.BranchID = BookedMinutes.BranchID
AND OpenDatesAndMinutes.[Date] = BookedMinutes.[Date]
AND OpenDatesAndMinutes.[Time] = BookedMinutes.[Time]
As you can imagine, joining on the branch, date & time with 13,000,000 rows all stored in CTE tables takes AGES - running it for a week isnt too bad, about 10 seconds but if we run it for 6 months (13,000,000 minutes) bloats to 25 minutes+
Once we have joined the open minutes to the booked minutes we then group the data on islands and present to the user:
CrossTabPrep ( [Date], [Time], [BranchID], [BookingCount], [Grp] )
AS ( SELECT [Date] ,
[Time] ,
[BranchID] ,
[BookingCount] ,
DATEPART(HOUR, Time) * 60 + DATEPART(MINUTE, Time) - ROW_NUMBER() OVER ( PARTITION BY [BranchID], Date, [BookingCount] ORDER BY Time ) AS [Grp]
FROM PreRender
),
FinalRender ( [BranchID], [Date], [Start Time], [End Time], [Duration], [EntryCount], [EntryColour] )
AS ( SELECT [BranchID] ,
[Date] ,
MIN([Time]) AS [Start Time] ,
MAX([Time]) AS [End Time] ,
ISNULL(DATEDIFF(MINUTE, MIN([Time]), MAX([Time])), 0) AS Duration ,
[BookingCount] AS EntryCount ,
CASE WHEN [BookingCount] = 0 THEN 'Red'
WHEN [BookingCount] = 1 THEN 'Green'
ELSE 'Yellow'
END AS EntryColour
FROM CrossTabPrep
GROUP BY [BranchID] ,
[Date] ,
[BookingCount] ,
[Grp]
)
Quite simply, is my method efficient? is there any way i can improve on this method whilst retaining minute level accuracy? When dealing with massive CTE tables such as this, would there be any benefit in dumping this data to indexed temp tables & joining them instead?
Another thing I was considering is replacing the DATE & TIME(0) data types that the big join uses, would is be more efficient if I cast these to integers?
Here is the Full CTE in case that helps:
WITH OpeningHours ( [BranchID], [DayOfWeek], [StartTime], [EndTime] )
AS ( SELECT BranchID ,
DayOfWeek ,
CONVERT(TIME(0), AM_open) ,
CONVERT(TIME(0), AM_close)
FROM db_BranchDetails.dbo.tbl_ShopOpeningTimes (NOLOCK)
INNER JOIN #tbl_Days Filter_Days ON db_BranchDetails.dbo.tbl_ShopOpeningTimes.DayOfWeek = Filter_Days.DayNumber
WHERE CONVERT(TIME(0), AM_open) <> CONVERT(TIME(0), '00:00:00')
UNION ALL
SELECT BranchID ,
DayOfWeek ,
CONVERT(TIME(0), PM_open) ,
CONVERT(TIME(0), PM_close)
FROM db_BranchDetails.dbo.tbl_ShopOpeningTimes (NOLOCK)
INNER JOIN #tbl_Days Filter_Days ON db_BranchDetails.dbo.tbl_ShopOpeningTimes.DayOfWeek = Filter_Days.DayNumber
WHERE CONVERT(TIME(0), PM_open) <> CONVERT(TIME(0), '00:00:00')
UNION ALL
SELECT BranchID ,
DayOfWeek ,
CONVERT(TIME(0), EVE_open) ,
CONVERT(TIME(0), EVE_close)
FROM db_BranchDetails.dbo.tbl_ShopOpeningTimes (NOLOCK)
INNER JOIN #tbl_Days Filter_Days ON db_BranchDetails.dbo.tbl_ShopOpeningTimes.DayOfWeek = Filter_Days.DayNumber
WHERE CONVERT(TIME(0), EVE_open) <> CONVERT(TIME(0), '00:00:00')
),
DateRange ( [Date], [DayOfWeek] )
AS ( SELECT CONVERT(DATE, DATEADD(DAY, N - 1, #StartDate)) ,
DATEPART(WEEKDAY, DATEADD(DAY, N - 1, #StartDate))
FROM tally (NOLOCK)
WHERE N <= DATEDIFF(DAY, #StartDate, #EndDate) + 1
),
OpenMinutes ( [BranchID], [DayOfWeek], [Time] )
AS ( SELECT [BranchID] ,
[DayOfWeek] ,
DATEADD(MINUTE, N - 1, StartTime)
FROM OpeningHours
LEFT OUTER JOIN tally ON tally.N BETWEEN 0
AND DATEDIFF(MINUTE, OpeningHours.StartTime, OpeningHours.EndTime) + 1
),
OpenDatesAndMinutes ( [Date], [Time], [BranchID] )
AS ( SELECT DateRange.[Date] ,
OpenMinutes.[Time] ,
OpenMinutes.BranchID
FROM DateRange
LEFT OUTER JOIN OpenMinutes ON DateRange.DayOfWeek = OpenMinutes.DayOfWeek
WHERE OpenMinutes.BranchID IS NOT NULL
),
WhiteListEmployees ( [DET_NUMBERA] )
AS ( SELECT DET_NUMBERA
FROM [dbo].[tbl_ChrisCache_WhiteList]
WHERE [TimeSheetV2_SecurityContext] = #TimeSheetV2_SecurityContext
),
BookedMinutesByRole ( [Date], [Time], [BranchID], BookingCount )
AS ( SELECT [BookingDate] ,
DATEADD(MINUTE, N - 1, StartTime) ,
BranchID ,
COUNT(BookingID) AS Bookings
FROM tbl_Booking (NOLOCK)
INNER JOIN tbl_BookingReason (NOLOCK) ON dbo.tbl_BookingReason.ReasonID = dbo.tbl_Booking.ReasonID
INNER JOIN tbl_ChrisCache (NOLOCK) ON dbo.tbl_Booking.DET_NUMBERA = dbo.tbl_ChrisCache.DET_NUMBERA
INNER JOIN #ValidPosCodes AS Filter_PostCodes ON dbo.tbl_ChrisCache.POS_NUMBERA = Filter_PostCodes.POSCODE
LEFT OUTER JOIN tally (NOLOCK) ON tally.N BETWEEN 0
AND DATEDIFF(MINUTE, tbl_Booking.StartTime, tbl_Booking.EndTime) + 1
WHERE ( Void = 0 )
AND tbl_BookingReason.CoverRequired = 0 --#### Only use bookings that dont require cover
AND tbl_booking.BranchID <> '023' --#### Branch 23 will always have messy data
AND ( dbo.tbl_Booking.BookingDate BETWEEN #StartDate
AND #EndDate )
GROUP BY [BookingDate] ,
BranchID ,
DATEADD(MINUTE, N - 1, StartTime)
),
BookedMinutesByWhiteList ( [Date], [Time], [BranchID], BookingCount )
AS ( SELECT [BookingDate] ,
DATEADD(MINUTE, N - 1, StartTime) ,
BranchID ,
COUNT(BookingID) AS Bookings
FROM tbl_Booking(NOLOCK)
INNER JOIN tbl_BookingReason (NOLOCK) ON dbo.tbl_BookingReason.ReasonID = dbo.tbl_Booking.ReasonID
INNER JOIN tbl_ChrisCache (NOLOCK) ON dbo.tbl_Booking.DET_NUMBERA = dbo.tbl_ChrisCache.DET_NUMBERA
INNER JOIN WhiteListEmployees Filter_WhiteList ON dbo.tbl_Booking.DET_NUMBERA = Filter_WhiteList.DET_NUMBERA
LEFT OUTER JOIN tally (NOLOCK) ON tally.N BETWEEN 0
AND DATEDIFF(MINUTE, tbl_Booking.StartTime, tbl_Booking.EndTime) + 1
WHERE ( Void = 0 )
AND tbl_BookingReason.CoverRequired = 0 --#### Only use bookings that dont require cover
AND tbl_booking.BranchID <> '023' --#### Branch 23 will always have messy data
AND ( dbo.tbl_Booking.BookingDate BETWEEN #StartDate
AND #EndDate )
GROUP BY [BookingDate] ,
BranchID ,
DATEADD(MINUTE, N - 1, StartTime)
),
BookedMinutes ( [Date], [Time], [BranchID], BookingCount )
AS ( SELECT [Date] ,
[Time] ,
[BranchID] ,
BookingCount
FROM BookedMinutesByRole
UNION
SELECT [Date] ,
[Time] ,
[BranchID] ,
BookingCount
FROM BookedMinutesByWhiteList
),
PreRender ( [Date], [Time], [BranchID], [BookingCount] )
AS ( SELECT OpenDatesAndMinutes.[Date] ,
OpenDatesAndMinutes.[Time] ,
OpenDatesAndMinutes.[BranchID] ,
ISNULL(BookedMinutes.BookingCount, 0) AS BookingCount
FROM OpenDatesAndMinutes
LEFT OUTER JOIN BookedMinutes ON OpenDatesAndMinutes.BranchID = BookedMinutes.BranchID
AND OpenDatesAndMinutes.[Date] = BookedMinutes.[Date]
AND OpenDatesAndMinutes.[Time] = BookedMinutes.[Time]
),
CrossTabPrep ( [Date], [Time], [BranchID], [BookingCount], [Grp] )
AS ( SELECT [Date] ,
[Time] ,
[BranchID] ,
[BookingCount] ,
DATEPART(HOUR, Time) * 60 + DATEPART(MINUTE, Time) - ROW_NUMBER() OVER ( PARTITION BY [BranchID], Date, [BookingCount] ORDER BY Time ) AS [Grp]
FROM PreRender
),
DeletedBranches ( [BranchID] )
AS ( SELECT [ShopNo]
FROM [dbo].[vw_BranchList]
WHERE [Branch_Deleted] = 1
),
FinalRender ( [BranchID], [Date], [Start Time], [End Time], [Duration], [EntryCount], [EntryColour] )
AS ( SELECT [BranchID] ,
[Date] ,
MIN([Time]) AS [Start Time] ,
MAX([Time]) AS [End Time] ,
ISNULL(DATEDIFF(MINUTE, MIN([Time]), MAX([Time])), 0) AS Duration ,
--dbo.format_timeV2(ISNULL(DATEDIFF(SECOND, MIN([Time]), MAX([Time])), 0)) AS DurationF ,
[BookingCount] AS EntryCount ,
CASE WHEN [BookingCount] = 0 THEN 'Red'
WHEN [BookingCount] = 1 THEN 'Green'
ELSE 'Yellow'
END AS EntryColour
FROM CrossTabPrep
GROUP BY [BranchID] ,
[Date] ,
[BookingCount] ,
[Grp]
)
SELECT [BranchID] ,
CONVERT(VARCHAR(10), DATEADD(DAY, 7, CONVERT(DATETIME, CONVERT(VARCHAR(10), DATEADD(day, -1 - ( DATEPART(dw, [Date]) + ##DATEFIRST - 2 ) % 7, [Date]), 103) + ' 23:59:59', 103)), 103) AS WeekEnding ,
[Date] ,
[Start Time] ,
[End Time] ,
[Duration] ,
CONVERT(VARCHAR, ( [Duration] * 60 ) / 3600) + 'h ' + CONVERT(VARCHAR, ROUND(( ( CONVERT(FLOAT, ( ( [Duration] * 60 ) % 3600 )) ) / 3600 ) * 60, 0)) + 'm' AS [DurationF] ,
[EntryCount] ,
[EntryColour] ,
CASE WHEN [EntryCount] = 0 THEN 'Red'
WHEN [EntryCount] >= 1 THEN 'Green'
END AS DurationColour ,
CASE WHEN [EntryCount] = 0 THEN 'This period of open-time isnt covered'
WHEN [EntryCount] >= 1 THEN 'This period of open-time is covered by ' + CONVERT(VARCHAR, [EntryCount]) + ' booking(s)'
END AS [DurationComment]
FROM FinalRender
WHERE FinalRender.BranchID NOT IN ( SELECT [BranchID]
FROM DeletedBranches )

Answer 1

It's funny, because you have answered your own question with your questions at the end. You should just try them all but to summarize:
Materialize CTEs for better performance. You never know when SQL Server will evaluate a CTE more than once
You can build indexex against temporary tables.
I'm not sure how you jumped from [DayOfWeek],DATEADD(MINUTE, N - 1, StartTime) to the join on [Date],[Time] on the other, but having two columns here doesn't make sense. Use either a single datetime or a bigint representing the seconds from an epoch. UnixTimestamp works well here.

Answer 2

My proposal is not based on your data, but on generated test data, so it can be not fully applicable.
Proposal: In order to move from quadratic degradation of performance to at least linear, batch processing can be used, if data is distributed equally among batch periods.
In example below 2 years of bookings is being processed with 3 day batch interval and it takes it 2 minutes and 30 seconds to get back free periods per day per branch.
Test run results:
2 years - 2 minutes and 30 seconds
4 years - 4 minutes and 55 seconds.
6 years - 6 minutes and 41 seconds
It incorporates the same logic that is being used in question by using numbers to find non-matching minutes.
Schema and test data creation:
IF OBJECT_ID('vwRandomNumber') IS NOT NULL
DROP VIEW vwRandomNumber
GO
IF OBJECT_ID('dbo.fnRandNumber') IS NOT NULL
DROP FUNCTION dbo.fnRandNumber
GO
IF OBJECT_ID('dbo.fnRandomInt') IS NOT NULL
DROP FUNCTION dbo.fnRandomInt
GO
IF OBJECT_ID('tblNumbers') IS NOT NULL
DROP TABLE dbo.tblNumbers
GO
IF OBJECT_ID('Branches') IS NOT NULL
DROP TABLE Branches
GO
IF OBJECT_ID('OpeningHours') IS NOT NULL
DROP TABLE OpeningHours
GO
IF OBJECT_ID('Bookings') IS NOT NULL
DROP TABLE Bookings
GO
CREATE VIEW vwRandomNumber
AS
SELECT Rand() RandomNumber;
GO
CREATE FUNCTION dbo.fnRandNumber()
RETURNS FLOAT
AS
BEGIN
RETURN (SELECT TOP 1 RandomNumber FROM vwRandomNumber)
END;
GO
CREATE FUNCTION dbo.fnRandomInt(#FromNumber INT, #ToNumber INT)
RETURNS INT
AS
BEGIN
RETURN (#FromNumber + ROUND(dbo.fnRandNumber()*(#ToNumber - #FromNumber),0))
END;
GO
CREATE TABLE tblNumbers
(
NumberID INT PRIMARY KEY
)
CREATE TABLE Branches
(
BranchID INT
,BranchName NVARCHAR(100)
);
GO
;WITH cteNumbers AS (
SELECT 1 N
UNION ALL
SELECT N+1 FROM cteNumbers WHERE N<100
)
INSERT INTO
Branches
SELECT N, CAST(NEWID() AS NVARCHAR(100)) FROM cteNumbers
OPTION(MAXRECURSION 0)
CREATE TABLE OpeningHours
(
BranchID INT
, Date DATETIME
, OpenFrom DATETIME
, OpenTo DATETIME
);
GO
CREATE CLUSTERED INDEX CIX_OpeningHours
ON OpeningHours ([Date], [BranchID])
GO
CREATE TABLE Bookings
(
BranchID INT
, BookingDate DATETIME
, BookingFrom DATETIME
, BookingTo DATETIME
)
CREATE CLUSTERED INDEX CIX_Bookings
ON Bookings ([BookingDate],[BranchID])
DECLARE #StartDate DATETIME = DATEADD(month,0,DATEADD(D,0,DATEDIFF(d,0,GETDATE())))
;WITH cteNumbers AS (
SELECT 1 N
UNION ALL
SELECT N+1 FROM cteNumbers WHERE N<2000
)
INSERT INTO
OpeningHours
(
BranchID
, Date
, OpenFrom
, OpenTo
)
SELECT
Branches.BranchID
, Dates.Day
, DATEADD(hour,7,Dates.Day)
, DATEADD(hour,19,Dates.Day)
FROM
(
SELECT
DATEADD(d,N,#StartDate) Day
FROM
cteNumbers
) Dates
CROSS JOIN
Branches
OPTION(MAXRECURSION 0);
INSERT INTO Bookings
SELECT
OpeningHours.BranchID
,OpeningHours.Date
,BookingHours.StartDate
,BookingHours.ToDate
FROM
OpeningHours
CROSS APPLY
(
SELECT DATEADD(hour, dbo.fnRandomInt(0,3), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(4,9), OpeningHours.OpenFrom) ToDate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(1,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(6,9), OpeningHours.OpenFrom) UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(2,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(5,8), OpeningHours.OpenFrom) TODate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(0,3), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(4,9), OpeningHours.OpenFrom) ToDate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(1,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(6,9), OpeningHours.OpenFrom) UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(2,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(5,8), OpeningHours.OpenFrom) TODate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(0,3), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(4,9), OpeningHours.OpenFrom) ToDate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(1,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(6,9), OpeningHours.OpenFrom) UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(2,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(5,8), OpeningHours.OpenFrom) TODate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(0,3), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(4,9), OpeningHours.OpenFrom) ToDate UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(1,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(6,9), OpeningHours.OpenFrom) UNION ALL
SELECT DATEADD(hour, dbo.fnRandomInt(2,5), OpeningHours.OpenFrom) StartDate
,DATEADD(hour, dbo.fnRandomInt(5,8), OpeningHours.OpenFrom) TODate
) BookingHours;
;WITH cteNumbers AS (
SELECT 1 N
UNION ALL
SELECT N+1 FROM cteNumbers WHERE N<5000
)
INSERT INTO
tblNumbers
SELECT N FROM cteNumbers
OPTION(MAXRECURSION 0)
--SELECT COUNT(*) FROM Bookings WHERE
Scripts to get periods with no bookings:
SET NOCOUNT ON
IF OBJECT_ID('tblBranchFreePeriods') IS NOT NULL
DROP TABLE tblBranchFreePeriods
IF OBJECT_ID('tblFreeMinutes') IS NOT NULL
DROP TABLE tblFreeMinutes
CREATE TABLE tblBranchFreePeriods
(
BranchID INT
, Date DATETIME
, PeriodStartDate DATETIME
, PeriodEndDate DATETIME
)
CREATE TABLE tblFreeMinutes
(
BranchID INT
,Date DATETIME
,FreeMinute INT
)
IF OBJECT_ID('dbo.tblStartDates') IS NOT NULL
DROP TABLE tblStartDates
CREATE TABLE tblStartDates
(
BranchID INT
, Date DATETIME
, PeriodStartDate DATETIME
)
CREATE CLUSTERED INDEX CIX_tblStartDates
ON tblStartDates([BranchID],[Date])
IF OBJECT_ID('dbo.tblEndDates') IS NOT NULL
DROP TABLE tblEndDates
CREATE TABLE tblEndDates
(
BranchID INT
, Date DATETIME
, PeriodEndDate DATETIME
)
CREATE CLUSTERED INDEX CIX_tblEndDate
ON tblEndDates ([BranchID],[Date])
CREATE CLUSTERED INDEX CIX_tblFreeMinutes
ON tblFreeMinutes ([BranchID],[Date],FreeMinute)
DECLARE #ProcessFromDate DATETIME, #ProcessTo DATETIME
SELECT #ProcessFromDate = MIN(OpenFrom), #ProcessTo = DATEADD(year,2,#ProcessFromDate) FROM OpeningHours
DECLARE #BatchSize INT = 3
DECLARE #StartTime DATETIME = GETDATE()
WHILE (#ProcessFromDate <= #ProcessTo) BEGIN
TRUNCATE TABLE tblFreeMinutes
TRUNCATE TABLE tblStartDates
TRUNCATE TABLE tblEndDates
SET #StartTime = GETDATE()
DECLARE #DateFrom DATETIME = #ProcessFromDate, #DateTo DATETIME = DATEADD(d,#BatchSize,#ProcessFromDate)
PRINT 'Date From ' + CAST(#DateFrom AS NVARCHAR(50))
PRINT 'Date To ' + CAST(#DateTO AS NVARCHAR(50))
INSERT INTO
tblFreeMinutes
SELECT
OpeningHours.BranchID
,OpeningHours.Date
,tblOpeningHourMinutes.NumberID Minute
FROM
OpeningHours
INNER JOIN
tblNumbers tblOpeningHourMinutes
ON
NumberID
BETWEEN DATEDIFF(minute,OpeningHours.Date,OpeningHours.OpenFrom)
AND
DATEDIFF(minute,OpeningHours.Date,OpeningHours.OpenTo)
LEFT OUTER JOIN
Bookings
ON
Bookings.BookingDate = OpeningHours.Date
AND
Bookings.BranchID = OpeningHours.BranchID
AND
tblOpeningHourMinutes.NumberID
BETWEEN
DATEDIFF(minute,Bookings.BookingDate,Bookings.BookingFrom)
AND
DATEDIFF(minute,Bookings.BookingDAte,Bookings.BookingTo)
WHERE
OpeningHours.Date BETWEEN #DateFrom AND #DateTo
AND
Bookings.BookingDate IS NULL
OPTION ( FORCE ORDER )
PRINT 'Populate free minutes ' + CAST(DATEDIFF(millisecond,#StartTime,GETDATE()) AS NVARCHAR(50))
SET #StartTime = GETDATE()
INSERT INTO
tblStartDates
SELECT
tblFreeMinutes.BranchID
, tblFreeMinutes.Date
, DATEADD(minute,tblFreeMInutes.FreeMinute,tblFreeMinutes.Date)
FROM
tblFreeMinutes
LEFT OUTER JOIN
tblFreeMinutes tblFreeMinutesIn
ON
tblFreeMinutesIn.Date = tblFreeMinutes.Date
AND
tblFreeMinutesIn.BranchID = tblFreeMinutes.BranchID
AND
tblFreeMinutesIn.FreeMinute = tblFreeMinutes.FreeMinute-1
WHERE
tblFreeMinutesIn.BranchID IS NULL
PRINT 'Populate start dates ' + CAST(DATEDIFF(millisecond,#StartTime,GETDATE()) AS NVARCHAR(50))
SET #StartTime = GETDATE()
INSERT INTO
tblEndDates
SELECT
tblFreeMinutes.BranchID
, tblFreeMinutes.Date
, DATEADD(minute,tblFreeMInutes.FreeMinute,tblFreeMinutes.Date)
FROM
tblFreeMinutes
LEFT OUTER JOIN
tblFreeMinutes tblFreeMinutesIn
ON
tblFreeMinutesIn.Date = tblFreeMinutes.Date
AND
tblFreeMinutesIn.BranchID = tblFreeMinutes.BranchID
AND
tblFreeMinutesIn.FreeMinute = tblFreeMinutes.FreeMinute+1
WHERE
tblFreeMinutesIn.BranchID IS NULL
PRINT 'Populate end dates ' + CAST(DATEDIFF(millisecond,#StartTime,GETDATE()) AS NVARCHAR(50))
SET #StartTime = GETDATE()
INSERT INTO
tblBranchFreePeriods
SELECT
tblStartDates.BranchID
, tblStartDates.Date
, tblStartDates.PeriodStartDate
, tblEndDate.PeriodEndDate
FROM
tblStartDates
CROSS APPLY
(
SELECT TOP 1
*
FROM
tblEndDates
WHERE
tblEndDates.BranchID = tblStartDates.BranchID
AND
tblEndDates.Date = tblStartDates.Date
AND
tblEndDates.PeriodEndDate > tblStartDates.PeriodStartDate
ORDER BY
PeriodEndDate ASC
) tblEndDate
PRINT 'Return intervals ' + CAST(DATEDIFF(millisecond,#StartTime,GETDATE()) AS NVARCHAR(50))
SET #StartTime = GETDATE()
SET #ProcessFromDate = DATEADD(d,#BatchSize+1,#ProcessFromDate)
PRINT ''
PRINT ''
RAISERROR ('',0,0) WITH NOWAIT
--SELECT * FROM tblBranchFreePeriods
--BREAK
END
SELECT
*
FROM
tblBranchFreePeriods
ORDER BY
1,2,3