One Youtube channel is the CMU Database Group from Carnegie Mellon University.  My brother went to CMU and one of his sons goes there now.  Their earlier series are...

To make the comparison between rows you could use the LAG function.  Then use integer division programYearValue/100 to extract the start year and take the modulo 100 of the lagged...

Why is there no primary key on the extractreports.dbo.partsrecomendationActive table?  You have a clustered index and yet UNIQUE is not specified.   This seems to cause a merge join and it's...

Regarding the time it takes different member have different approaches.  For me it's usually asap without too much nth degree refactoring.  Whatever gets people unstuck.  I'm a developer too so...

Happy it helps!  Thanks for the feedback 😊

It was a medium challenge.  Your follow up post cleared up the lot size issue.  Maybe an hour or so added together.  Estimating...

Thanks for the further explanation.  This query takes a number of passes at the data due to multiple uses of windowing functions. It assumes 'Item' to be a PARTITION BY...

Is this the equation?  The change in monthly quantity is labelled as delta_q.

quantity_on_hand + delta_q + production_proposal - lot_size - minimum_stock = 0

In month 1:

quantity_on_hand=4,000, delta_q=0, lot_size=810, and minimum_stock=4050

4,000+0+production_proposal-810-4050=0

production_proposal=860

In month...

Before calculating the ytd amounts you could first summarize to the month.  Then CROSS APPLY to get ytd amounts

drop table if exists #myfacttable;
go
create table #myfacttable(
  businessdate...

where OrderDate>=dateadd(day, 1, eomonth(getdate(), -1))
      and OrderDate<datefromparts(year(getdate()), month(getdate()), 16)

It seems there are 3 compound conditions: 1)  where (drive=c and percentage free<10), or 2) where (drive!=c and percentage free<20), and 3) where not (server=vc5 and drive in (...)).  Maybe...

Also add PARTITION BY ID to the SELECT INTO

SELECT *, 
       LAG(ReportDate) OVER (partition by id ORDER BY ReportDate) LagReportDate,
 ...

/* Add LAG function columns to the query which...

If you add the LAG columns to #MyData you could try CROSS JOIN'ing the calendar rows with the distinct IDs.  Then LEFT JOIN #MyData on id and date.

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