get a recursive parent list

Question

Using MySQL, I want to return a list of parents, from a table that has a field structure like this. ID,PARENTID,NAME (a standard parent-child hierarchy). I would like to tra

Answer 1

Here, I made a little function for you, I checked it in my database (MAMP) and it works fine

use mySchema;
drop procedure if exists getParents;

DELIMITER $$
CREATE PROCEDURE getParents (in_ID int)
BEGIN
DROP TEMPORARY TABLE IF EXISTS results;
DROP TEMPORARY TABLE IF EXISTS temp2;
DROP TEMPORARY TABLE IF EXISTS temp1;

CREATE TEMPORARY TABLE temp1 AS
  select distinct ID, parentID
    from tasks
    where parentID = in_ID;

create TEMPORARY table results AS
  Select ID, parentID from temp1;

WHILE (select count(*) from temp1) DO
  create TEMPORARY table temp2 as
    select distinct ID, parentID 
      from tasks 
      where parentID in (select ID from temp1);

  insert into results select ID, parentID from temp2;
  drop TEMPORARY table if exists temp1;
  create TEMPORARY table temp1 AS
    select ID, parentID from temp2;
  drop TEMPORARY table if exists temp2;

END WHILE;


select * from results;

DROP TEMPORARY TABLE IF EXISTS results;
DROP TEMPORARY TABLE IF EXISTS temp1;

END $$
DELIMITER ;

this code will return all parents to any depth. you can obviously add any additional fields to the results

use it like this

call getParents(9148)

for example