數據表t的ddl：
create table t(class char(1),callcount int,calldate date)


sql語句:

select calldate,

sum(case class when '1' then callcount else 0 end) as A類,

sum(case class when '2' then callcount else 0 end) as B類,

sum(case class when '3' then callcount else 0 end) as C類

from t group by calldate

最后結果：