Question

Ok then guys, this is embarassing. I am getting this PHP error, already linted, checked code and don’t get the answer. Any suggestion?

**Warning**: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in file.php on line **, heres the complete code

<?
session_start();

include 'keys.php';

include 'EpiCurl.php';
include 'EpiOAuth.php';
include 'EpiTwitter.php';
?>

As additional data, it pushes data correctly to databases but interrupts the following part of the code.

UPDATE: The problem was in the “require” files, not in the code I posted, I was using this code: while($results = mysql_fetch_array($results)) { in where I repeated 2 $results

Answer 1

You’re assuming that mysql_query() with a SELECT statement always returns a resultset resource. This is not the case. Quote from mysql_query() documentation:

For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning
resultset, mysql_query() returns a resource on success, or FALSE on
error.

For other type of SQL statements, INSERT, UPDATE, DELETE, DROP, etc,
mysql_query() returns TRUE on success or FALSE on error.

Thus, in case of error you end up passing a boolean FALSE value to mysql_fetch_array() instead of a resultset. This is why one should check whether the value returned by mysql_query() is FALSE before passing it to other functions as a resultset.

UPDATE: Apparently the code we were shown was different from the one actually causing the problem. The problem was caused by passing a return value from mysql_fetch_array() back to it on a second call:

while($results = mysql_fetch_array($results))

Either way, passing a value which isn’t a resultset to mysql_fetch_array() was the cause of the issue exactly as the error message said:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in file.php on line