I worked through many of these when discussed here 7 months ago https://news.ycombinator.com/item?id=12022953 ... really enjoyable, great refresher, and learned some things I never knew before.
The PostgreSQL exercises web [1] is an awesome intro to basic and medium level topics.
It has been discussed previously in HN [2].
[1] https://pgexercises.com/
[2] https://news.ycombinator.com/item?id=12022953
I worked through many of these when discussed here 7 months ago https://news.ycombinator.com/item?id=12022953 ... really enjoyable, great refresher, and learned some things I never knew before.