MySQL query order if null

Question

I am trying to build a MySQL query that has order by expression. This is what I am trying to do:

SELECT * FROM tbl_product ORDER BY retail_price ONLY IF wholesale_price IS NULL OTHERWISE ORDER BY wholesale_price. 

I don’t know where to start. I found an article that uses ORDER BY COALESCE, but I also found that this might have performance issues.

Any advice is appreciated.

Answer 1

 SELECT * FROM tbl_product ORDER BY ifnull(wholesale_price, retail_price); 

Please note that you do not need to select the value that you order - it can be any expression