Get all products under a given collection [duplicate] - php

Question

This question already has answers here:
How to create a MySQL hierarchical recursive query?
(16 answers)
Closed 4 years ago.
I have a MYSQL table called collections when viewed and implemented as a table could be something like this:
I needed to know whether one mysql query will be able to get all the products under a collection type entry (a given) which could have collections under it. For example, if I select 10, it should return 14, 12, 13, and 15.
I implemented a solution that involves a do..while loop...
$concatted = 10;
$products = [];
do {
$sql = "SELECT id, type FROM collections WHERE parent IN ($id_concatted)";
$result = $mysqli->query($sql);
if($result) {
while($row = $result->fetch_object()){
if($row->type == 'product') {
apply_changes_to_product($row->id);
} elseif ($row->type=='collection'){
$collections[] = $row->id;
}
}
}
if(count($collections) > 0){
$id_concatted = implode($collections, ",");
$continue = true;
$collections = [];
} else {
$continue = false;
}
} while ($continue);
I think that the above code is not efficient. I think it is doable with one query but I don't know how.
UPDATE: I mark this as a duplicate of How to create a MySQL hierarchical recursive query although in that post there is NO accepted solution. I got myself this solution based on one reply there (Mysql 5.6):
SELECT id, `type` FROM (
select id, `type`
from (select * from collections
order by parent, id) products_sorted,
(select #pv := '10') initialisation
where find_in_set(parent, #pv)
and length(#pv := concat(#pv, ',', id))
) products
WHERE
products.`type` = 'product'
The fiddle is http://sqlfiddle.com/#!9/ea214f/2.

Answer 1

yes, you may need to use subquery and first fetch id where parent = selectedId and type = 'collection' and then select id where parent in the subquery id and type = 'product'
Like below:
SELECT id, type FROM collections WHERE parent IN (select id from collections where
parent = $id_concatted and type = 'collection') and type = 'product'
For Multiple level, Use Recursive feature of MySql. Like below:
WITH RECURSIVE COLLECTIONS_PRODUCTS (ID, TYPE, PATH)
AS
(
SELECT ID, TYPE, CAST(ID AS CHAR(200))
FROM COLLECTIONS
WHERE PARENT IN ($id_concatted)
UNION ALL
SELECT S.ID, S.TYPE, CONCAT(M.PATH, ",", S.ID)
FROM COLLECTIONS_PRODUCTS M JOIN COLLECTIONS S ON M.ID=S.PARENT
)
SELECT * FROM COLLECTIONS_PRODUCTS WHERE TYPE = 'product' ORDER BY PATH;