Sorry, sorry my apologies.  I didn't catch the inconsistency.  The green arrows in the image you posted only point up!  Afaik that's the part I missed.  Once there's an...

Here is a slightly different approach.  There is no discernable difference in the performance for the sample data.  When I add a primary key on Number and StartTime, this approach...

• This reply was modified 4 weeks, 1 day ago by  drew.allen. Reason: Changed COUNT to SUM

Another thing.  In cases such as this, it's usually best to start a new post and reference the old post instead of hijacking the original post.  Otherwise it can get...

The problem is that your data is stored as closed intervals (both end-points are included in the interval) when this issue requires half-closed intervals (only one end-point is included in...

LAG, which compares rows within the window partition, is not strictly necessary imo.  JOIN relates to a lookup table containing the values sequence.  Also, I'm not a fan of...

ORs can be quite expensive, so I wrote up this version that uses a different method.  This would probably perform better if you had a separate table that defined the...

ID isn't necessary.  The combination of CommunityID and PersonID should be unique, because a person cannot belong to a community multiple times.  Since you already have a unique key, I...

First, the VALUES clause can take more than one set of values, so you can take advantage of that to make your script MUCH more concise.

insert into #T(VisitID,...

Thanks for the critical feedback! I appreciate your point, but the intent of my script wasn't to compare performance between the two methods. It was focused on providing a...

No, I caught that.  You stated that there is...

I've almost completely abandoned this approach since the introduction of STRING_AGG(), because it's just so much simpler to implement (and therefore easier to understand).  You need to offer a compelling...

From the T-SQL Documentation: Slash Star (Block Comment) (Transact-SQL)

"Nested comments are supported. If the /* character pattern occurs anywhere within an existing comment, it is treated as the start...

It looks like there may also be an error in your logic.  ANDs are evaluated before ORs, and, based on your layout, that's not how you want the WHERE clause...

• This reply was modified 2 months, 2 weeks ago by  drew.allen.
• This reply was modified 2 months, 2 weeks ago by  drew.allen. Reason: Edited to put in missing end quotes

Not sure why you failed to post sample data and expected results, but you did...

An IF...ELSE is a Control-of-Flow element.  It cannot be used inside of atomic statements, because that would make them non-atomic.  I believe that WHERE clauses can only appear in atomic...