When PostgreSQL's case

Select TT.Dict_labelAs Display_item, T1.ratioFrom
(Select T.Product_level,RoundSumCase when T.detect_result=' 2 'Then1Else0End)::numeric/Count1)::NUMERIC,4)As ratio
from T_detect_record t 
 where t.district= ' 3 ' and t.e_commerce_platform= group by T.product_level) T1 
  Left JOIN T_dict tt  Product_level=tt. dict_value 
 where Tt.dict_type= ' product_level ' 
 
 
       

Select Country, sum (case if sex = ' 1 ' then population else 0 End), -- male population

SUM (case if sex = ' 2 ' then population else 0 end) -- female population

from table_a    by country;

When PostgreSQL's case