Does anyone know where something close to documentation for the SQL that Apache Spark implements? I mean an extensive listing of every operator, library function, keywords, etc. Similar to Microsoft and T-SQL. I am doing kind of trial and error right now
As @David Griffin said in comment, Spark SQL comes from Hive.
And on Spark's website, it says:
Spark SQL reuses the Hive frontend and metastore, giving you full compatibility with existing Hive data, queries, and UDFs. Simply install it alongside Hive.
So you should look into Hive Documentation