在相关排序的sql中提升特色结果

Question

I have a DB table of jobs. The table has a column 'featured' = NULL or 1.

A user can search the table using keywords. And I sort them by relevancy, date, or salary, like below (relevancy):

SELECT SQL_CALC_FOUND_ROWS *, MATCH(`title`) 
            AGAINST ("*'.$keywords.'*") 
            AS Relevance 
            FROM jobs2 
            WHERE MATCH(`title`) 
            AGAINST ("*'.$keywords.'*") 
            ORDER BY Relevance
            LIMIT 0,50

I want any jobs that are 'featured' to be first on each page (but each featured job still in order themselves).

eg if a natural search was to return (in order):

Job1  not featured
Job2  not featured
Job3  featured
Job4  not featured
Job5  featured

I want featured jobs at the top in order like:

Job3  featured
Job5  featured
Job1  not featured
Job2  not featured
Job4  not featured

How can I achieve this? Ideally in the SQL query itself if possible

Answer 1

Well, if you simply want all of the featured ones first of all the listings, you can just sort by two columns:

SELECT SQL_CALC_FOUND_ROWS *, MATCH(`title`) 
  AGAINST ("*'.$keywords.'*") 
  AS Relevance 
  FROM jobs2 
  WHERE MATCH(`title`) 
  AGAINST ("*'.$keywords.'*") 
  ORDER BY featured desc, Relevance desc -- <-- This here
  LIMIT 0,50

If instead you want to have the featured listings first on each page but not to impact the overall sorting otherwise, you can do it either in your application logic, or use the same query as a subquery and reorder its results:

SELECT * from 
  (SELECT SQL_CALC_FOUND_ROWS *, MATCH(`title`) 
    AGAINST ("*'.$keywords.'*") 
    AS Relevance 
    FROM jobs2 
    WHERE MATCH(`title`) 
    AGAINST ("*'.$keywords.'*") 
    ORDER BY Relevance desc
    LIMIT 0,50) AS X
ORDER BY X.featured desc, X.Relevance desc;