Can’t get all the results using fetch(PDO::FETCH_ASSOC); - php

Question

I am trying to get a list of sites ids according to a user id.
This is what I've got so far.
public function getSites() {
$stmt = $this->db->prepare("SELECT Sites_idSites FROM favorites WHERE User_idUser=:idUser");
$userId = $_SESSION['user_session']['idUser'];
$stmt->bindparam(":idUser", $userId);
$stmt->execute();
$siteList = $stmt->fetchAll(PDO::FETCH_ASSOC);
foreach($siteList as $value) {
foreach($value as $key) {
$stmt = $this->db->prepare("SELECT * FROM sites WHERE idSites=:siteList");
$stmt->bindparam(":siteList", $key);
}
$stmt->execute();
$userSites = $stmt->fetch(PDO::FETCH_ASSOC);
}
return $userSites;
This is the part that I go to "favorites" table and get all the site's ids that correspond to the user id.
$stmt = $this->db->prepare("SELECT Sites_idSites FROM favorites WHERE User_idUser=:idUser");
$userId = $_SESSION['user_session']['idUser'];
$stmt->bindparam(":idUser", $userId);
$stmt->execute();
$siteList = $stmt->fetchAll(PDO::FETCH_ASSOC);
$siteList return as an array like this:
Array
(
[0] => Array
(
[Sites_idSites] => 20
)
[1] => Array
(
[Sites_idSites] => 21
)
[2] => Array
(
[Sites_idSites] => 22
)
)
Now, I want to go to the table where all the sites are and only get the ones with those ids.
This is what I am using, but it only gets the last one:
foreach($siteList as $value) {
foreach($value as $key) {
$stmt = $this->db->prepare("SELECT * FROM sites WHERE idSites=:siteList");
$stmt->bindparam(":siteList", $key);
}
$stmt->execute();
$userSites = $stmt->fetch(PDO::FETCH_ASSOC);
}
If I do print_r($userSites), I will return:
Array
(
[idSites] => 22
[name] => rwrwer
[url] => werwerwerwer
[Category_idCategory] => 1
)
As you can see, it is only returning the last one. How do I make it return an array with all the sites in it? Am I doing something wrong?
I finally fixed it:
public function getSites() {
$stmt = $this->db->prepare("SELECT sites.* FROM favorites INNER JOIN sites ON favorites.Sites_idSites = sites.idSites WHERE favorites.User_idUser = :idUser");
$userId = $_SESSION['user_session']['idUser'];
$stmt->bindparam(":idUser", $userId);
$stmt->execute();
$siteList = $stmt->fetchAll(PDO::FETCH_ASSOC);
return $siteList;
}

Answer 1

This is because you are running the query outside of the inner loop where you bind the values.
foreach($siteList as $value){
foreach($value as $key){
$stmt = $this->db->prepare("SELECT * FROM sites WHERE idSites=:siteList");
$stmt->bindparam(":siteList",$key);
// Bind and rebind, so only the last one "Sticks"
}
// Run the query after the loop
$stmt->execute();
$userSites = $stmt->fetch(PDO::FETCH_ASSOC);
}
You are basically rebinding the :siteList on each iteration. Then when you run it, only the last time you bound it "sticks". Also fetch will only return a single row (at least without looping over it).
You could just move that inside of the loop and then do fetchAll, but a better way is to build a list and then use IN() like this:
foreach($siteList as $value){
$i = 0;
$ids = [];
$where = [];
$sql = 'SELECT * FROM sites WHERE';
foreach($value as $key){
$placeholder = ":id_{$i}";
$where[] = $placeholder;
$ids[$placeholder] = $key;
++$i;
}
$this->db->prepare($sql . ' idSites IN( ' . implode(',', $where) . ' )');
$stmt->execute($ids);
$userSites = $stmt->fetchAll(PDO::FETCH_ASSOC);
}
The SQL should look like this:
SELECT * FROM sites WHERE idSites IN( :id_1,:id_2,:id_3 )
And the $ids array should look like this
$ids = [':id_1'=>1,':id_2'=>53,':id_3'=>1239];
Except, I just made up those numbers (obviously).
This way, you can reduce the number of queries you execute. You may even be able to put it outside of the loop(s) entirely, but without more context I can't really say that. The basic thing is, is that calling the database is expensive and you should endeavor to do so as few times as possible.