从mysql返回结果，使用用户函数

Question

请告诉，为什么这段代码错了？

function myres() { 
    $db = new mysqli("localhost","userrr","pass","mvc"); 
    $res = $db->query("SELECT * FROM news "); 
    return $res; 
} 


while ($row = myres()->fetch_row()) { 
    echo $row[0]; 
} 

P.S. 此代码工作：

$db = new mysqli("localhost","userrr","pass","mvc"); 
$res = $db->query("SELECT * FROM news "); 
while ($row = $res->fetch_row()) { 
    echo $row[0]; 
} 

Answer 1

在这里，您拨打myres()每一次，我想：

while ($row = myres()->fetch_row()) { 
    echo $row[0]; 
} 

所以每次$row包含结果的第一行，它不会停止。它会工作正常，我认为：

$res = myres(); 

while ($row = $res->fetch_row()) { 
    echo $row[0]; 
}