Mysql Variables does not work via php mysql query

I have this query:

$query = " 

 SET @points := -1;
 SET @num := 0;

 SELECT `id`,`rank`,
 @num := if(@points = `rank`, @num, @num + 1) as `point_rank`
 FROM `said`
 ORDER BY `rank` *1 desc, `id` asc";

I'm using this query from php; giving me this error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SET @num := 0;

If I copy and paste that code in phpmyadmin Sql query panel, it works perfectly, but from the php code lines it's not working, seems like there's an issues while setting Vars.

---

Instead of setting the variables in a separate SET, have you tried using a CROSS JOIN:

$query = " 

SELECT `id`,
  `rank`,
  @num := if(@points = `rank`, @num, @num + 1) as `point_rank`
FROM `said`
CROSS JOIN (SELECT @points:=-1, @num:=0) c
ORDER BY `rank` *1 desc, `id` asc";