[qohen]

A couple of sites worth checking out to level up, both by Markus Winand:

https://modern-sql.com/

https://use-the-index-luke.com/

[oulipo2]

also a few different para-sql languages that can be useful, to lower the complexity:

- https://prql-lang.org/ - https://www.malloydata.dev/

[efromvt]

A self para-sql-lang plug if you like the direction of malloy but prefer something closer to native SQL syntax. (a controversial take at times)

- https://trilogydata.dev/

[CobaltFire]

I ran across https://use-the-index-luke.com organically while learning SWL recently and I've been really enjoying it.

I can't vouch for it from any perspective except as an SQL neophyte but for me it has been teaching me a lot.