pdo query not executing when passing a variable as the query - php

Question

I have a pdo command like this $sql = $pdoObj->execute($query) but it does not work, 0 result returning. I echo'ed out the $query variable just before calling execute() and then pasted it inside the execute() and the code ran successfully. I can't understand what is the problem here as I have done this in other parts of my code without problems.
Here are some examples of the queries:
SELECT s.id, s.marca, s.colore, s.prezzo, i.id_scarpa, i.taglia FROM scarpe AS s INNER JOIN info_scarpe AS i ON i.id_scarpa = s.id WHERE 1 = 1 AND taglia IN ('40','41','42') AND colore IN ('rosso', 'nero')
SELECT * FROM scarpe WHERE 1=1
SELECT * FROM scarpe WHERE 1=1 AND marca IN ('adidas','nike')
They are all dynamic generated queries based on the $_GET variable.
EDIT:
Sure
if ( isset($_GET) ) {
if ( isset($_GET['taglia']) ) {
$query = "
SELECT
s.id, s.marca, s.colore, s.prezzo, i.id_scarpa, i.taglia
FROM
scarpe AS s
INNER JOIN
info_scarpe AS i
ON i.id_scarpa = s.id
WHERE
1 = 1
";
foreach ( $_GET as $index => $val ) {
$a = explode(',', $val);
$in = "'" . implode("','", $a) . "'";
$query .= ' AND '.$index.' IN ('.$in.')';
}
} else {
$query = " SELECT * FROM scarpe WHERE 1=1";
foreach ( $_GET as $index => $val ) {
$a = explode(',', $val);
$in = "'" . implode("','", $a) . "'";
$query .= ' AND '.$index.' IN ('.$in.')';
}
}
echo 'data loaded';
} else {
$query = " SELECT * FROM scarpe ORDER BY id DESC ";
}
EDIT2:
I use query() and not execute() but still does not work

Answer 1

The arguments for execute should be an array with query parameters. You mean to use either
$result = $pdoObj->query($query);
OR
$stmt = $pdoObj->prepare($query);
$stmt->execute();