Now rlike is not supported in calcite, i think it's useful to support this so that it can be used in other engine depending on calcite.
Calcite SQLParser: Provide support for RLIKE expressions
Add support for Regular Expression Operators (RLIKE)
Add ILIKE operator (similar to LIKE, but case-insensitive, and PostgreSQL-specific)
GitHub Pull Request #2341
GitHub Pull Request #2363