Conditional Sum and Count in Crystal Reports -

is there way can change formula field code:

if(isnull(sum({col1}))) 0 else sum({col1}) 

to like: sum(col1) col2='a'? calculate rows in sum based on value of column.

in case there is, please provide me syntax or way it.

p.s: in case matters i'm using crystalreports 13.0 whith visual studio 2010

you can this.

in details write formula

if col2='a' col1 else 0 

now take sum in footer