Flink SQL reserves certain strings as keywords, even if the corresponding SQL features are not yet fully implemented. If you use a reserved keyword as an identifier (such as a table name or field name) in a DDL statement, wrap it in backticks.
Example: `value`
Reserved keywords by version
For the full list of reserved keywords for your Flink version, see the Apache Flink documentation:
Flink 1.12: Reserved Keywords
Flink 1.13: Reserved Keywords
Flink 1.15: Reserved Keywords