dbms: removed limit for at least two elements in tuple [#METR-18020].

dbms/include/DB/Core/ErrorCodes.h

@@ -20,7 +20,6 @@ namespace ErrorCodes
 		POSITION_OUT_OF_BOUND = 11,
 		PARAMETER_OUT_OF_BOUND = 12,
 		SIZES_OF_COLUMNS_IN_TUPLE_DOESNT_MATCH = 13,
-		EMPTY_TUPLE = 14,
 		DUPLICATE_COLUMN = 15,
 		NO_SUCH_COLUMN_IN_TABLE = 16,
 		DELIMITER_IN_STRING_LITERAL_DOESNT_MATCH = 17,

dbms/include/DB/Functions/FunctionsMiscellaneous.h

@@ -422,9 +422,6 @@ public:
 	/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
 	DataTypePtr getReturnType(const DataTypes & arguments) const
 	{
-		if (arguments.size() < 2)
-			throw Exception("Function " + getName() + " requires at least two arguments.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
-
 		return new DataTypeTuple(arguments);
 	}