How to Pass Variable into a MySQL Stored Procedure from PHP

Question

I have the following stored procedure:

proc_main:begin

declare done tinyint unsigned default 0;
declare dpth smallint unsigned default 0;


create temporary table hier(
 AGTREFERRER int unsigned, 
 AGTNO int unsigned, 
 depth smallint unsigned default 0
)engine = memory;

insert into hier values (p_agent_id, p_agent_id, dpth);

/* http://dev.mysql.com/doc/refman/5.0/en/temporary-table-problems.html */

create temporary table tmp engine=memory select * from hier;

while done <> 1 do

  if exists( select 1 from agents a inner join hier on a.AGTREFERRER = hier.AGTNO and hier.depth = dpth) then

    insert into hier 
      select a.AGTREFERRER, a.AGTNO, dpth + 1 from agents a
      inner join tmp on a.AGTREFERRER = tmp.AGTNO and tmp.depth = dpth;

    set dpth = dpth + 1;      

    truncate table tmp;
    insert into tmp select * from hier where depth = dpth;

  else
    set done = 1;
  end if;

end while;


select 
 a.AGTNO,
 a.AGTLNAME as agent_name,
 if(a.AGTNO = b.AGTNO, null, b.AGTNO) as AGTREFERRER,
 if(a.AGTNO = b.AGTNO, null, b.AGTLNAME) as parent_agent_name,
 hier.depth,
 a.AGTCOMMLVL
from 
 hier
inner join agents a on hier.AGTNO = a.AGTNO
inner join agents b on hier.AGTREFERRER = b.AGTNO
order by
 -- dont want to sort by depth but by commission instead - i think ??
 -- hier.depth, hier.agent_id; 
 a.AGTCOMMLVL desc;

drop temporary table if exists hier;
drop temporary table if exists tmp;

end proc_main

While the function does its job well - it only currently allows sorting via AGTCOMMLVL descending order. The stored procedure's purpose is to match a memberID with their parentID and associated COMMLVL. Once paired appropriately,I use the memberID in a second query to return information about that particular member.

I would like to be able to sort by any number of filters but have the following problems:

1. I can't seem to find a way to pass a variable into the stored procedure altering its sorting by field.

2. Even if I could - the sort may actually only contain data from the second query (such as first name, last name, etc)

3. Running a sort in the second query does nothing even though syntax is correct - it always falls back to the stored procedure's sort.

any ideas?

EDIT

My php uses mysqli with code:

$sql = sprintf("call agent_hier2(%d)", $agtid);
$resulta = $mysqli->query($sql, MYSQLI_STORE_RESULT) or exit(mysqli_error($mysqli));

Answer 1

$stmt = $dbh->prepare("CALL sp_takes_string_returns_string(?)");
$value = 'hello';
$stmt->bindParam(1, $value, PDO::PARAM_STR|PDO::PARAM_INPUT_OUTPUT, 4000); 

// call the stored procedure
$stmt->execute();

print "procedure returned $value\n";

Answer 2

If you want to sort by input parameter of the stored procedure, you need to use Prepared staments For example,

DELIMITER //
CREATE  PROCEDURE `test1`(IN field_name VARCHAR(40) )
BEGIN
  SET @qr = CONCAT ("SELECT * FROM table_name ORDER BY ",  field_name);

  PREPARE stmt FROM @qr;
  EXECUTE stmt;
  DEALLOCATE PREPARE stmt;
END //