private String fieldDefinitions() {
        return fieldDefinitions.stream()
                .map(MySqlFieldDefinition::toDdl)
                .collect(Collectors.joining(", \n\t"));
    }
used to generate table definition in ddl with "desc table".
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/mysql-cdc/src/main/java/org/apache/inlong/sort/cdc/mysql/schema/MySqlTableDefinition.java