Posted by Erland Sommarskog on 09/30/96 11:51

Frank (mrpubnight@hotmail.com) writes:
> Basically there are tables that track history and each table tends to
> track only a specific value housed within a date range. I'm trying to
> combine the tables to get a snap-shot of the complete history. I'm
> having problems dealing with the Start/End Dates from the two tables
> and building the dates in the final table to be broken down by 'history
> type'.
>
> Here are a few sample records and the results I'm trying to achieve:
>
> Table 1:
> CAgyHist (ProdID,AgyID,StartDate,EndDate)
> 1 1 Jan 1, 2006 Jan 5, 2006
> 1 2 Jan 5, 2006 Jan 25, 2006
> 1 1 Jan 25, 2006 NULL
>
> Table 2:
> CInvHist (ProdID, InvID,StartDate,EndDate)
> 1 1 Jan 1, 2006 Jan 23, 2006
> 1 2 Jan 23, 2006 Jan 15, 2006
> 1 1 Jan 15, 2006 NULL
>
> Desired End Result:
> CTotalHist (ProdID,AgyID,InvID,StartDate,EndDate)
> 1 1 1 Jan 1, 2006 Jan 5, 2006
> 1 2 1 Jan 5, 2006 Jan 15, 2006
> 1 2 2 Jan 15, 2006 Jan 23, 2006
> 1 2 1 Jan 23, 2006 Jan 25, 2006
> 1 1 1 Jan 25, 2006 NULL
>
> My challenge thus far has been dealing with the dates as they don't
> necessarily correspond - from one table to the other.

There should be a fair chance to this in a query (or possibly two
with help of some temp table). But since it's bit complex, the hour
is late, and your sample data is unclear, I prefer to ask for
clarification:

1) What are the keys of these tables?
2) What do they signify?
3) What is the combined table supposed to describe?
4) Is that interval from Jan 23 to Jan 15 intentional or is a typo?
In the latter case, can you provide an updated sample?
--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

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