How to avoid MySQL "Commands out of sync" error

I have a php while loop that I need to increment through a MySQL multi query. The first time around, it writes to the database as intended. But as soon as it loops around once, I get the following Query Error:

Commands out of sync; you can't run this command now

Here's the loop containing the query:

$i = 285;
while ( $i <= 286 ) {
	$sql = "
			schoolid = 0 
			AND planid >= 8000
			AND planid <= 8005;	
		UPDATE links_temp SET linkid = NULL, schoolid = {$i} WHERE 
			schoolid = 0;
		INSERT INTO links SELECT * FROM links_temp;
	$result = mysqli_multi_query( $conn, $sql ) or die( "Query Error: " . mysqli_error( $conn ) );

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What do I need to do to enable this query to loop successfully?
Jonathan GreenbergAsked:
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lcohanDatabase AnalystCommented:
"This can happen, for example, if you are using mysql_use_result() and try to execute a new query before you have called mysql_free_result(). It can also happen if you try to execute two queries that return data without calling mysql_use_result() or mysql_store_result() in between."
Chris StanyonWebDevCommented:
When running a multi query, you need to loop through all result sets before moving on. If you don't need to retrieve anything from the DB, then you can effectively flush the result sets with calls to mysqli_next_result():

    $result = mysqli_multi_query( $conn, $sql ) or die( "Query Error: " . mysqli_error( $conn ) );
    while(mysqli_more_results($conn)) {

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Jonathan GreenbergAuthor Commented:

Thank you SO much - it would have taken me hours to figure that out!

Chris StanyonWebDevCommented:
No worries Jonathan. Glad I could help :)
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