Updating heartReactions value in json using the postID inside the json - php

Question

My code.
try
{
$sql = "SELECT posts FROM posts WHERE entityid = ?";
$stmt = $pdo->prepare($sql);
$stmt->execute([$data["entityId"]]);
$result = $stmt->fetchAll();
$sqlq = "UPDATE posts set posts= JSON_SET(posts,'$.heartReactions', ?) WHERE posts(posts,'$.postId',$postId)";
$stmt = $pdo->prepare($sqlq);
$posts = json_decode($result[0][0]);
$postId = $data["postId"];
for ($i = 0; $i < count($posts); $i += 1)
{
$post = $posts[$i];
if ($post->postId == $data["postId"])
{
if ($data["heartState"] == 1)
{
$post->heartReactions += 1;
}
else if ($data["heartState"] == -1)
{
$post->heartReactions -= 1;
}
$postData = $post->heartReactions;
var_dump($stmt->execute([$postData]));
echo $postData;
// echo $post->heartReactions . " - ";
if ($data["laughState"] == 1)
{
$post->laughReactions += 1;
}
else if ($data["laughState"] == -1)
{
$post->laughReactions -= 1;
}
// echo $post->laughReactions;
break;
}
}
}
catch (PDOException $ex)
{
echo $ex;
}
I want to change the key value "heartReactions" from 0 to 1. But it didn't change at all. Also I got an error.
Warning: Undefined variable $postId in D:\xammp\htdocs\AlumniSystemMainFinal\server\functions\pages\profile.php on line 112
PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1 in D:\xammp\htdocs\AlumniSystemMainFinal\server\functions\pages\profile.php:133
Stack trace:
#0 D:\xammp\htdocs\AlumniSystemMainFinal\server\functions\pages\profile.php(133): PDOStatement->execute(Array)
#1 {main}