Seems to be an odd recursive thing, where for each row you compute a SubtractionResult, with SubtractionResult=ColumnValue-(SubtractionResult from previous row, or 0 if no previous row).

Fairly simple to...

30% of the table's rows is the optimizer's guess on rows returned from an inequality predicate when it can't use statistics.

In this case, that's most likely from your...

On the linked server + CASE thing, see Paul White's answer at https://dba.stackexchange.com/questions/42837/why-do-linked-servers-have-a-limitation-of-10-branches-in-a-case-expression

Cheers!

The other possibility is that the subquery is simply returning no rows, which would also result in the assignment of NULL.

Further, the query as posted wouldn't even execute,...

You're doing this backwards.

With the PATINDEX you've written, you're checking for the existence of any character that ISN'T a number.

If you can't find a non-number (PATINDEX...

Question already asked in an ongoing thread at  https://www.sqlservercentral.com/Forums/1890134/Using-PATINDEX-To-Determine-If-A-String-Is-Alpha.

Best to direct responses there.

On that note, please don't post the same question in multiple threads. It splits...

Glad to help!

Biggest thing is the lack of a PARTITION BY in the OVER clause.

With multiple instance_names you'll want to do that; otherwise you're just getting whatever the previous counter...

Page splits...*shudders*

Hmmm...add indexing to the DBA? I guess you can write on yourself... 🙂

Here's another sort of approach. It relies on some assumptions about your data (all and only rows with 'Y' for flag have a non-null value for Period; the value for...

First things first: you're doing it yet again, namely posting the same question repeatedly under new topics. If you haven't received a reply in a few days, then bumping the...