select count(case when value=0 then 1 end)/count(case when value>0 then 1 end) 
from tb

------解决方案--------------------
select sum(if(value>0,1,0))/count(*)  
from tt


------解决方案--------------------
select (select count(*) from table1 where value>0)/(select count(*) from table1);

------解决方案--------------------
探讨


引用:

引用:

select (select count(*) from table1 where value>0)/(select count(*) from table1);


假如，我要求：
value的和（sum)、value大于0的和（sum）、value的行数、value大于0的行数
……