select nullif(count(distinct col1),0) from table1 ;

create view counts4 AS select nullif(count(distinct col1),0) from table1 ;

select * from counts4;

/* SQL Error (1064): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '<cache>(count(distinct `testdb5`.`table1`.`col1`)),0) AS `nullif(count(distinct ' at line 1 */

CREATE DATABASE IF NOT EXISTS `testdb5` 

USE `testdb5`;

CREATE TABLE IF NOT EXISTS `table1` (

  `col1` varchar(50) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;