Hacker News Reader

I made this: https://www.windowfunctions.com

Are you asking for “sharing skills” as in something like StackOverflow, but for SQL?

I would think there already is a Stack Exchange for SQL, possibly several (for different RDBMSes/ dialects); go have a look there, if this is what you meant.

Are you asking for examples of advanced SQL skills?

In my experience, if you can grok lateral joins (aka cross apply), recursive CTEs, window functions, and fully understand all the join types, that's a gold star for understanding SQL!

I would add indexes to that list. Knowing the different types and how they impact performance can be very valuable.

I didn't add indexes mainly b/c for analytic warehouses that are columnar, indexes are less important / meaningless. Partitions though, that's important!