mysql order by issue

Question

if i have a query like :

SELECT * FROM table  WHERE id IN (3,6,1,8,9);

this array of the ids is build in php dynamically , and the order is

Answer 1

You can order by a value derived from a column. You can use a CASE operator to specify the order:

SELECT * FROM table
WHERE id IN (3,6,1,8,9)
ORDER BY CASE id WHEN 3 THEN 1
                 WHEN 6 THEN 2
                 WHEN 1 THEN 3
                 WHEN 8 THEN 4
                 WHEN 9 THEN 5
         END