为什么mysqli fetch在函数中创建一个无限循环？

Question

Why does this function return an infinite loop? I am trying to create a function where you just have to give it the query and the while loop takes care of the rest. but for some reason ONLY when i have the function return $q->fetch_assoc() it goes into an infinite loop. if I return just $q, then call $q->fetch_assoc() in the while loop then it doesn't cause the infinite loop.

public function fetch($query){
    $con = $this->con;
    $q = $con->query($query);

    return $q->fetch_assoc();
}

while($r = $sqli->fetch("SELECT id FROM users LIMIT 5")){
    echo $r['id']."<br />";
}

also tried

public function fetch($query){
    $con = $this->con;
    $q = $con->query($query);

    return $q->fetch_assoc();
}

$x = $sqli->fetch("SELECT id FROM users LIMIT 5");

while($r = $x){
    echo $r['id']."<br />";
}

I thought maybe it was recreating a new fetch function every time. This too did not work and caused the infinite loop.

Answer 1

Every time you call the function you RE-RUN the query, which resets the data set to the first record.

e.g. You have 5 records that get returned:

function get() {
    .... run query
    return 1st record
}

You'll NEVER get records 2,3,4,5 because you keep resetting the query to the beginning.

Your function should be returning the result HANDLE:

function do_query($sql) {
    $result = $con->query($sql);
    return $result;
}

while($row = $result->fetchRow()) {
   ...
}