For those who are curious, here is the ANTLR grammar specification for Spark SQL.

https://github.com/apache/spark/blob/master/sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

An adaptation of Presto’s presto-parser/src/main/antlr4/com/facebook/presto/sql/parser/SqlBase.g4 grammar