Question

I am new to rails. Here is the following code with Foo as model object:

a = Foo
a = Foo.where(age: 18)
if params[:sort] == "desc"
  a = a.order("name desc") 
end

Here two queries are performed, I want to combine them to one or you can say i want to perform Foo.where(age=18).order("name asc")

Remember there can be the case when order is no needed i.e. params[:sort] is not equal to desc.

Please don’t give solution like

if params[:sort] == "desc"
    a = a.where(age=18).order("name desc") 
else
    a = a.where(age=18)
end

as it makes code redundant and also for more parameters it might not work.

Answer 1

No, you’re mistaken. Actually, no queries are performed here.

a = Foo
a = Foo.where(age=18)
if params[:sort] == "desc"
  a = a.order("name desc") 
end

The actual query is sent where you start retrieving data. That is, do something like

a.each do |b|
  # do something with b
end

Until then you can safely chain criteria building methods (where, order, select and others).