## Logic to break period of time by month

 Author Message mario17 Hall of Fame Group: General Forum Members Points: 3314 Visits: 683 Hi,Can anybody give me and idea if it's possible, I need to check the following table and do some logic counting period of time but withing each of month, so let say for id=303 with period = 45, I'll get 3 records ,etc:` 303 6/27/13 8/11/13 45 || \/ 1 303 6/27/13 6/30/13 32 303 7/01/13 7/31/13 313 303 8/01/13 8/11/13 11 `Is there any date function to do this in TSQL?my sample data`with ttt as (select 123 Id, DATEADD(d,-10,getdate()) fromDD, DATEADD(d,-3,getdate()) toDD, datediff(d, DATEADD(d,-10,getdate()), DATEADD(d,-3,getdate())) period ,1000 prodID unionselect 202 Id, DATEADD(d,-25,getdate()) fromDD, DATEADD(d,-17,getdate()) toDD, datediff(d, DATEADD(d,-25,getdate()), DATEADD(d,-17,getdate())) period ,2000 prodID unionselect 303 Id, DATEADD(d,-55,getdate()) fromDD, DATEADD(d,-10,getdate()) toDD, datediff(d, DATEADD(d,-55,getdate()), DATEADD(d,-10,getdate())) period ,3000 prodID )select * from ttt`Thanks Mario Jamie Ingram-729524 SSC Eights! Group: General Forum Members Points: 929 Visits: 448 If you just want the difference between the dates in the two columnsdatediff(mm,col1,col2) + 1 to include the first montheg select datediff(mm,'6/27/13','8/11/13') +1CheersJamie We are the pilgrims, master. We shall go always, a little further. dwain.c SSC-Forever Group: General Forum Members Points: 44151 Visits: 6431 I believe you can do it something like this.`with ttt as ( select 123 Id, DATEADD(d,-10,getdate()) fromDD, DATEADD(d,-3,getdate()) toDD, datediff(d, DATEADD(d,-10,getdate()), DATEADD(d,-3,getdate())) period ,1000 prodID union select 202 Id, DATEADD(d,-25,getdate()) fromDD, DATEADD(d,-17,getdate()) toDD, datediff(d, DATEADD(d,-25,getdate()), DATEADD(d,-17,getdate())) period ,2000 prodID union select 303 Id, DATEADD(d,-55,getdate()) fromDD, DATEADD(d,-10,getdate()) toDD, datediff(d, DATEADD(d,-55,getdate()), DATEADD(d,-10,getdate())) period ,3000 prodID ), Tally (n) AS ( SELECT number FROM [master].dbo.spt_values Tally WHERE [Type] = 'P' AND Number BETWEEN 1 AND 100)SELECT id, fromDD=MIN(d.DD), toDD=MAX(d.DD), period=COUNT(*), prodID FROM ttt aCROSS APPLY (SELECT n FROM Tally WHERE n BETWEEN 1 AND period+1) cCROSS APPLY (SELECT [month]=DATEPART(month, a.fromDD+n-1),DD=CAST(a.fromDD+n-1 AS DATE)) dGROUP BY id, prodID, [month]`Note that if you have a period > 100 days, then you'll need a bigger Tally table (examples abound). You can also do this with a Calendar table but that might be a little harder to explain.Not sure if you really need that last CAST to DATE but you did show your expected results as a DATE and not a DATETIME. My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!My thought question: Have you ever been told that your query runs too fast?My advice:INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.Need to UNPIVOT? Why not CROSS APPLY VALUES instead?Since random numbers are too important to be left to chance, let's generate some!Learn to understand recursive CTEs by example.Splitting strings based on patterns can be fast!My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables mario17 Hall of Fame Group: General Forum Members Points: 3314 Visits: 683 see familiar fish, Thanks so much Dwain !!!!BestM mario17 Hall of Fame Group: General Forum Members Points: 3314 Visits: 683 Is it possible to assign level (count for how many parts (months) it was broken for each ID),` 303 6/27/13 8/11/13 45 || \/level 1 303 6/27/13 6/30/13 32 303 7/01/13 7/31/13 313 303 8/01/13 8/11/13 11`Tx again,Jamie thansk for your post. I got you point, then I can do inpivot. Bestmario dwain.c SSC-Forever Group: General Forum Members Points: 44151 Visits: 6431 mario17 (8/22/2013)Is it possible to assign level (count for how many parts (months) it was broken for each ID),` 303 6/27/13 8/11/13 45 || \/level 1 303 6/27/13 6/30/13 32 303 7/01/13 7/31/13 313 303 8/01/13 8/11/13 11`Tx again,Jamie thansk for your post. I got you point, then I can do inpivot. BestmarioAdd an outer select to get a ROW_NUMBER():`SELECT Level=ROW_NUMBER() OVER (PARTITION BY id ORDER BY fromdd) ,id, fromDD, toDD, period, prodIDFROM ( SELECT id, fromDD=MIN(d.DD), toDD=MAX(d.DD), period=COUNT(*), prodID FROM ttt a CROSS APPLY (SELECT n FROM Tally WHERE n BETWEEN 1 AND period+1) c CROSS APPLY (SELECT [month]=DATEPART(month, a.fromDD+n-1),DD=CAST(a.fromDD+n-1 AS DATE)) d GROUP BY id, prodID, [month] ) a` My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!My thought question: Have you ever been told that your query runs too fast?My advice:INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.Need to UNPIVOT? Why not CROSS APPLY VALUES instead?Since random numbers are too important to be left to chance, let's generate some!Learn to understand recursive CTEs by example.Splitting strings based on patterns can be fast!My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables ScottPletcher SSC-Forever Group: General Forum Members Points: 46442 Visits: 8044 You should use your own tally table, either a permanent one or a dynamically generated one. Since the permanent one would be clustered on the tally value, it might give better performance. I'm using a tally CTE in the code below to allow it to be run independently. [Reason: Aside from the danger that master.dbo.spt_values could be modified, or removed, at any time by MS, you don't want your application needing authority to read from the master db to be able to run!]You can then do an INNER JOIN to the tally table to expand the months; the tally value conveniently also provides the level -- nice!`;WITH ttt AS ( select 123 Id, DATEADD(d,-10,getdate()) fromDD, DATEADD(d,-3,getdate()) toDD, datediff(d, DATEADD(d,-10,getdate()), DATEADD(d,-3,getdate())) period ,1000 prodID union all select 202 Id, DATEADD(d,-25,getdate()) fromDD, DATEADD(d,-17,getdate()) toDD, datediff(d, DATEADD(d,-25,getdate()), DATEADD(d,-17,getdate())) period ,2000 prodID union all select 303 Id, DATEADD(d,-55,getdate()) fromDD, DATEADD(d,-10,getdate()) toDD, datediff(d, DATEADD(d,-55,getdate()), DATEADD(d,-10,getdate())) period ,3000 prodID),--select * from tttcteDigits AS ( SELECT 0 AS digit UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9),cteTally AS ( SELECT [10s].digit * 10 + [1s].digit AS tally FROM cteDigits [1s] CROSS JOIN cteDigits [10s])SELECT t.tally + 1 AS Level, ttt.Id, CONVERT(varchar(8), CASE WHEN t.tally = 0 THEN ttt.fromDD ELSE DATEADD(MONTH, DATEDIFF(MONTH, 0, ttt.fromDD) + t.tally, 0) END , 1) AS fromDD, CONVERT(varchar(8), CASE WHEN DATEDIFF(MONTH, ttt.fromDD, ttt.toDD) = 0 OR DATEADD(MONTH, t.tally, ttt.fromDD) > ttt.toDD THEN ttt.toDD ELSE DATEADD(DAY, -1, DATEADD(MONTH, DATEDIFF(MONTH, 0, ttt.fromDD) + t.tally + 1, 0)) END , 1) AS toDD, DATEDIFF(DAY, CASE WHEN t.tally = 0 THEN ttt.fromDD ELSE DATEADD(MONTH, DATEDIFF(MONTH, 0, ttt.fromDD) + t.tally, 0) END, CASE WHEN DATEDIFF(MONTH, ttt.fromDD, ttt.toDD) = 0 OR DATEADD(MONTH, t.tally, ttt.fromDD) > ttt.toDD THEN ttt.toDD ELSE DATEADD(DAY, -1, DATEADD(MONTH, DATEDIFF(MONTH, 0, ttt.fromDD) + t.tally + 1, 0)) END) + 1 AS PeriodFROM tttINNER JOIN cteTally t ON t.tally BETWEEN 0 AND DATEDIFF(MONTH, ttt.fromDD, ttt.toDD)ORDER BY Id, Level` SQL DBA,SQL Server MVP(07, 08, 09) Prosecutor James Blackburn, in closing argument in the Fatal Vision murders trial: If in the future, you should cry a tear, cry one for them [the murder victims]. If in the future, you should say a prayer, say one for them. And if in the future, you should light a candle, light one for them. mario17 Hall of Fame Group: General Forum Members Points: 3314 Visits: 683 Thanks, ScottYour code works fine, and much easy to digest ( or learn if you will), amazing.. and thanks again to you and Dwain for sharing this, sure you can read this in books...-)BTW, Scottyour code produces not correct results if you go beyound 210 days or so, I played with it and found this.So curious why/where it could happened, tally I think works just fine, it has 100 rows ( for 100 days?), but it still works fine on d,-209 and start breaking on d,-210. (toDD = today = getdate().You can see looking at toDD for last level, it set to 8/31/13 ` select 303 Id, DATEADD(d,-210,getdate()) fromDD, getdate() toDD, datediff(d, DATEADD(d,-210,getdate()), getdate()) period ,3000 prodID`Best to allM mario17 Hall of Fame Group: General Forum Members Points: 3314 Visits: 683 Dwain,trying to reverse eng your super code, is this a place to use Cross Apply ONLY, or could be done with Join.I can't get second Cross Apply`--CROSS APPLY (SELECT n FROM Tally WHERE n BETWEEN 1 AND period+1) cinner join #Tally on N between 1 and Period+1CROSS APPLY (SELECT [month]=DATEPART(month, a.fromDD+n-1),DD=CAST(a.fromDD+n-1 AS DATE)) d`Thank againM dwain.c SSC-Forever Group: General Forum Members Points: 44151 Visits: 6431 mario17 (8/23/2013)Dwain,trying to reverse eng your super code, is this a place to use Cross Apply ONLY, or could be done with Join.I can't get second Cross Apply`--CROSS APPLY (SELECT n FROM Tally WHERE n BETWEEN 1 AND period+1) cinner join #Tally on N between 1 and Period+1CROSS APPLY (SELECT [month]=DATEPART(month, a.fromDD+n-1),DD=CAST(a.fromDD+n-1 AS DATE)) d`Thank againMINNER JOIN like that should work assuming your Tally table is in a temporary table. I have a preference for CROSS APPLY.Are you saying you don't understand what the second CROSS APPLY is doing?Basically it just does some intermediate calculations. [month] is just the month number which is used later to group the results. DD is the start date + the tally value (-1 to adjust the offset so first n=0). My mantra: No loops! No CURSORs! No RBAR! Hoo-uh!My thought question: Have you ever been told that your query runs too fast?My advice:INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.Need to UNPIVOT? Why not CROSS APPLY VALUES instead?Since random numbers are too important to be left to chance, let's generate some!Learn to understand recursive CTEs by example.Splitting strings based on patterns can be fast!My temporal SQL musings: Calendar Tables, an Easter SQL, Time Slots and Self-maintaining, Contiguous Effective Dates in Temporal Tables