PHP Common Errors Call fetch_assoc on boolean


If you get an error like this:

Fatal error: Call to a member function fetch_assoc() on boolean in C:\xampp\htdocs\stack\index.php on line 7

Other variations include something along the lines of:

mysql_fetch_assoc() expects parameter 1 to be resource, boolean given...

These errors mean that there is something wrong with either your query (this is a PHP/MySQL error), or your referencing. The above error was produced by the following code:

$mysqli = new mysqli("localhost", "root", "");
$query = "SELCT * FROM db"; // notice the errors here
$result = $mysqli->query($query);
$row = $result->fetch_assoc();

In order to "fix" this error, it is recommended to make mysql throw exceptions instead:

// add this at the start of the script

This will then throw an exception with this much more helpful message instead:

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'SELCT * FROM db' at line 1

Another example that would produce a similar error, is where you simply just gave the wrong information to the mysql_fetch_assoc function or similar:

$john = true;
mysqli_fetch_assoc($john, $mysqli); // this makes no sense??