I use HafSQL a lot. I don't typically use HAF directly as it is for very specific uses. As for documentation, I believe we are fairly lacking and most is from the examples and tests in Gitlab.
With examples and tests in Gitlab are you referring to the ones in: https://gitlab.syncad.com/hive/hive?
If so, could you direct me to the section with the documentation of HafSQL or give me a link where I can find more info about the HafSQL version you are currently using in case it's outside of: https://gitlab.syncad.com/hive/haf?
With examples and tests in Gitlab are you referring to the ones in:
No, that's Hive Node code. It depends on what you are trying to build.
The best would probably be looking at the official apps built on HAF.
For most people, I don't think you would be using HAF. Haf is mainly for apps you would run on a Hive Node and hopefully get distributed to other Hive nodes so it is decentralized.
Otherwise, you would likely be using RPC or SQL calls.