Hi,

I found that mysqli_more_results() return true when there is more than 
1 query

<?php
$link = mysqli_connect("localhost", "root", "123456", "test");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$query  = "SELECT 1;";
$query  .= "SELECT 1;"; // second query

/* execute multi query */
if (mysqli_multi_query($link, $query)) {
    var_dump(mysqli_more_results($link)); 
}

?>

bool(true)

However, this behavior is totally confused

Exactly what is confusing here? Your first script does single query -> there are no more results than the one. So why would mysqli_more_results() return true since there are no more results..?

The problem is mysqli_more_results($conn) needs to be called first to 
check if there is at least one result returned.

The code below is valid if I make a single query that returns multiple 
result set 

mysqli_multi_query($conn, $query);

while (mysqli_more_results($conn))
{
    mysqli_next_result($query);

    /* store first result set */
    if ($result = mysqli_store_result($conn)) {
 
    }
}

When I use mysqli_multi_query() I may not know how many queries are 
there in $query. Therefore I would like to use mysqli_more_results() 
to check if I can loop through the result sets. It is the same as in 
array iteration

Single element: array(1)    => using for: yes
2 elements:     array(1, 2) => using for: yes

But when it comes to mysqli_multi_query()

Single element: array(1)    => using while: no
2 elements:     array(1, 2) => using while: yes

Because mysqli_multi_query() deals with multiple result sets, it is 
expected to have unified iteration interface for both single result 
set and multiple result sets.

Also the behavior is defined in PHP Manual that 

"Indicates if one or more result sets are available from a previous 
call to mysqli_multi_query()."

It means that mysqli_more_results($conn) must return true in my case

mysqli_multi_query($conn, $query);

while (mysqli_more_results($conn))
{

}

because in fact I do not know if there is any result returned at all 
after calling mysqli_multi_query(). So while 
(mysqli_more_results($conn)) is a good way to do if any.

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

Your code is wrong. There will always be one result set which will be active. mysqli_more_results() will tell you whether there is yet another result set but you're on the last (and only) result set so there's no other.

Perhaps this should be written more clearly in the docs. I though also it works differently.