Order by most matched records first

Question

Given the following query:

select * from users 
where first_name ilike '%foo%' 
OR last_name ilike '%bar%' 
OR nickname ilike '%foobar%'

Returns:

 first_name| last_name   |  nickname
----------------------------------------
  Foo      | ABC         |   abcd
  Foo      | DEF         |   efgh
  Foo      | BAR         |   ijkl
  AMD      | Bar         |   foobar
  Foo      | Bar         |   foobar2

Question:

How to sort most relevant (matched) values first? I mean by most matched that matches more than one pattern inside Where .. OR

Expected Result:

 first_name| last_name   |  nickname
----------------------------------------
  Foo      | Bar         |   foobar2
  Foo      | BAR         |   ijkl
  AMD      | Bar         |   foobar
  Foo      | ABC         |   abcd
  Foo      | DEF         |   efgh

Answer 1

Order it by the number of hits:

... ORDER BY (first_name ILIKE '%foo%')::integer 
           + (last_name  ILIKE '%bar%')::integer
           + (nickname   ILIKE '%foobar%')::integer DESC