mysql rows to columns

https://stackoverflow.com/questions/1241178/mysql-rows-to-columns

MySQL - Rows to Columns

 

select
  d2.host_id,
  ifnull(sum(d2.A),0) as A,
  ifnull(sum(d2.B),0) as B,
  ifnull(sum(d2.C),0) as C
from
  (select
    demo2.*,
    case when item_name='A' then item_value end as A,
    case when item_name='B' then item_value end as B,
    case when item_name='C' then item_value end AS C
 	 from demo2) AS d2
GROUP by d2.host_id;