/* WHY DOES THIS WORK ... */

select 
	killer, 												
	(count('')) as kills,								
	(SELECT count('') from actions where killer='KillerMan' and corpse=a.killer and type='kill') as deaths	
from actions as a where corpse = 'KillerMan' AND type='kill' group by killer order by kills desc

/* ... BUT NOT THIS? */


select 
	killer, 												
	(count('')) as kills,								
	(SELECT count('') from actions where killer='KillerMan' and corpse=a.killer and type='kill') as deaths,
	(kills/deaths) as ratio
from actions as a where corpse = 'KillerMan' AND type='kill' group by killer order by kills desc