Implemented an alternative SQL parser for ClickHouse based on the ANTLR4 runtime and generated from an EBNF grammar.
Why it matters
This feature introduces a new SQL parser to provide a more flexible and maintainable parsing solution for ClickHouse. By using ANTLR4 and EBNF grammar, it aims to improve parsing accuracy, ease future grammar updates, and enhance overall SQL parsing robustness for users.How to use it
The new ANTLR4-based SQL parser is integrated into ClickHouse. Users can utilize it transparently as the default or alternative parser depending on the ClickHouse version and configuration, without needing explicit commands. Details on enabling or switching parsers, if available, should be found in the official documentation.