case problem.sql

/* basic testcase: */
create table `stats` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `gender` char(1) DEFAULT 'U',
  PRIMARY KEY (`id`)
  );
  
  
insert into `stats` (gender) values ('M'), ('F'), ('U'), ('M'), ('F'), ('U'), (''), (''), (null), (null);

/* simplified query */
SELECT 

CASE gender WHEN 'M' THEN "Male" WHEN 'F' THEN "Female" ELSE 'Unknown' END AS gender,  

count(gender) as `count` 
FROM stats

/*WHERE 1 = 1*/

group by gender
order by gender;

/* Sample output:
Female	2
Male	2
Unknown	2
Unknown	2
Unknown	0 */