Cheers for the tip. It's trying to execute @ColNames as the literal string whereas I would like to feed the results of @ColNames. Maybe using something like an output ?

Thanks. I tried with the additional CTE but it didn't reduce execution time.

@micheal-2, the .exe is part of the historian meant to handle large amounts of time series data. The sproc is here down the line for ingestion in our...

Thanks guys for the feedback as I understand the question was quite vague. Having previously worked as an analyst, most of the the work I did was building the queries...

Thanks all. Worked perfectly. I used Scott's inline example - matched what i needed plus extra bonus explanation.

Brilliant. Thanks a ton. Perhaps I've oversimplified my example which makes the data model unclear also I think the data hasn't been properly loaded which leaves NULL's in place where...

The way my data is structured one group only has one name associated to it, spread across multiple guid's. So group 1 could have 18 guid's which should all have...

Looking at group1, it has the guid1 and guid3 associated it. If I look at the GuidTable I can check that guid1 has Alex but guid3 has NULL. The logic...