mysql - Check row exist or not in Ruby on Rails -

i new ruby on rails , have basic knowledge of mysql. using mysql db. question -- how check if row exists or not in table. have tried code it's not going straight else block, not if block:

@tasks = user.find_by("user_name = ? , password = ?", params[:user_name], params[:password]) if @tasks   redirect_to action: 'index', status: 302 else   redirect_to action: 'detail', status: 302 end 

if want find if user given name , password exists using ruby on rails, can this:

user.where(user_name: params[:user_name], password: params[:password]).exists? 

see railsguides: existence of objects.

the cause of original problem?

so code original poster submitted:

user.find_by("user_name = ? , password = ?", "#{params[:user_name]}", "#{params[:password]}") 

i removed string interpolation because unnecessary

user.find_by("user_name = ? , password = ?", params[:user_name], params[:password]) 

and apparently fixed problem. i'm not sure why make difference though, interpolated string should same value values in params dictionary.