Parse (or EXPLAIN) the SQL for better analysis - for auto index candidates and detecting unsupported corner cases.

[OndraZizka]

We could use:

1. HSQLDB's SQL parser - available right away but not a clear API,
2. JOOQ SQL parser https://www.jooq.org/doc/latest/manual/sql-building/sql-parser/
3. Apache Calcite
4. JSQLParser

Alternatively, we could just run an EXPLAIN query, and perhaps HSQLDB will provide info usable for that.