Adam Black

And sorry for not tagging someone earlier. I'm not always sure where to put things. The OHDSI/Odysseus communication surface area is quite large!

Playing around with this idea for `union`... Seems promising but there are two cases where it fails ("starts" and "finished by"). Are analytic functions (lag and lead) more efficient than...

Just wondering if it's possible to have some intuition about which query is faster. I'll try testing them. I really only need two sorts (by start date and end date)...

Some initial comparison results. SQL Server Union All looks considerably faster on sql server Redshift less of a difference on redshift. Here's the query I'm running which probably still needs...

> I looked it over a few times but I'm having trouble seeing the difference in the code. Here is a diff with the updated code on the left and...

Yea I see. I think you might be right. I was curious about trying to find the end_dates without needing the "union all" step. But the example you showed is...

@chrisknoll would this query work for getting start and end dates? It removes the join and union all. How would I test all possible cases? ``` with cte1 as (...

Wow, thanks for this detailed guidance Chris. I'll try to write up a complete response in the next few days.

Hi @chrisknoll, I want to work through three topics: 1. intuition, 2. correctness, and 3. performance of the algorithm. I am indeed interested in getting both start and end dates....

Thanks Chris. 1:30! Hope you're sleeping in this morning!! There's a lot to respond to but I found something I wanted to run past you. I'm trying to implement the...