Github user haohui commented on a diff in the pull request: https://github.com/apache/flink/pull/4128#discussion_r140702758 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/functions/sql/ScalarSqlFunctions.scala --- @@ -33,6 +33,14 @@ object ScalarSqlFunctions { OperandTypes.NILADIC, SqlFunctionCategory.NUMERIC) + val BIN = new SqlFunction( + "BIN", + SqlKind.OTHER_FUNCTION, + ReturnTypes.explicit(SqlTypeName.VARCHAR), + null, + OperandTypes.NUMERIC, --- End diff -- You can construct a checker easily using `OperandTypes.or()` in Calcite.
---