select sum(case when score between 90 and 100 then 1 else 0 end) as A,

sum(case when score between 80 and 89 then 1 else 0 end) as B,

sum(case when score between 70 and 79 then 1 else 0 end) as C,

sum(case when score between 60 and 69 then 1 else 0 end) as D,

sum(case when score<60 then 1 else 0 end) as E

from z_experiment_score