database variables calculation in ruby

[monica23]

Hi everybody, in my database, am trying to print the value of total and then add it to the price,
i was able to fetch the value of total but when i tried to add it to to price so as to get value of sum in this line
of code

 
    sum = price + %s, row[0]  
    puts "sum"
 

nothing happens. where am i supposed to perform the operations, is outside the loop. below is the code, any help please

 
    #!/Ruby19/bin/ruby 
    require 'cgi'
 
    cgi = CGI.new
    puts cgi.header
 
    require "dbi"
 
 
 
     price = '100'
    begin
       # connect to the MySQL server
         conn = DBI.connect("DBI:Mysql:db:localhost", 
                            "root", "root566")
 
        rs = con.query("SELECT total from product where product_id = '20'")
 
       row = stmt.fetch do
 
       end
       puts "<font color=green size=4><b>get total values</b></font><br><br>"
 
     printf '<b>total:</b> %s<br>', row[0]
 
     sum = price + %s, row[0]  
    puts "sum"
 
 
 
    rescue Mysql::Error => e
        puts e.errno
        puts e.error
 
    ensure
        con.close if con
    end