Select query custom calculated column to round to 2 decimal places

I have a table with some columns a,b, i need to add a custom column c_avg which will have the value c_avg = a*100/b upto 2 decimal values my original table is some thing like this ``` id a b 1 1 2 2 2 3 3 2 0 ``` I have come up with this query but seems as this returns me value as integer. ``` select round( CAST((CASE WHEN b=0 THEN '0.00' ELSE round(((a*100)/b),2) END ) as numeric) , 2) as c_avg from table_name ``` i get output to this as ``` a b c_avg 1 2 0 2 3 0 ``` i need some thing like this ``` a b c_avg 1 2 0.50 2 3 0.66 2 0 0 ``` My Postgresql version on amazon redshift is PostgreSQL 8.0.2 There is also a few things I'm doing with this table ``` select sum(a) as aa, sum(b) as bb, groub_by_column round( CAST((CASE WHEN sum(b)=0 THEN '0.00' ELSE round(((sum(a)*100)/sum(b)),2) END ) as numeric) , 2) as c_avg from table group by groub_by_column ``` This returns me value to 0 and not to 0.* Thanks The division operation in postgresql truncates to integer value just found that ``` select round((4000/576::float),3) as result; ``` adding meta ::float to the division operation gives the desired result, it does not truncates the output to integer value. Thanks