后续调用mysqli_fetch_object会返回下一行吗？

Question

I want to know is every subsequent call to mysqli_fetch_object will return the next row within the result set just as mysqli_fetch_row? or why is the while loop needed in the following code:

while($obj=mysqli_fetch_object($result)){
    printf("%s %s
", $obj->lastname, $obj->age);
}

Answer 1

I would strongly recommend looking into the PHP docs on a function to see how it operates. This doc page should help you digest and understand what it actually does.

In Summary

In short what you have used as an example will take $result, which is a myqsli_query() result and create an object for the current row.

The while loop is in place to loop through the entire query results. In turn, this creates an object (under the same variable $obj) for every row.

One example extracted from the docs:

$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";

if ($result = mysqli_query($link, $query)) {

/* fetch associative array */
while ($obj = mysqli_fetch_object($result)) {
    printf ("%s (%s)
", $obj->Name, $obj->CountryCode);
}

/* free result set */
mysqli_free_result($result);
}

Returning, for example

Pueblo (USA)
Arvada (USA)
Cape Coral (USA)
Green Bay (USA)
Santa Clara (USA)

P.S. If you use Sublime Text, this plugin is marvelous in jumping to the docs: https://github.com/kemayo/sublime-text-2-goto-documentation