PHP: can't encode json with multiple rows

Question

I\'ve spent a couple of hours looking through several the similar answers before posting my problem.

I\'m retrieving data from a table in my database, and I want to

Answer 1

I must have spent 15 hours on this issue. Every variation discussed above was tried. Finally I was able to get the 'standard solution' working. The issue, very oddly, appears to be this:

When the interval is set beyond 14 hours, json appears to be unable to parse it. There must be a limit to JSON.

$sql= "SELECT cpu_name, used, timestamp FROM tbl_cpu_use WHERE timestamp>(NOW() - INTERVAL 14 HOUR) ORDER BY id";
$result=mysql_query($sql);
if ($result){
    $i=0;
    $return =[];
    while($row = mysql_fetch_array($result, MYSQL_NUM)){
        $rows[] = $row;
    }
    echo json_encode($rows);
}else{
    echo "ERROR";
}