ID: 50462
Comment by: pcdinh at gmail dot com
Reported By: pcdinh at gmail dot com
Status: Feedback
Bug Type: MySQLi related
Operating System: Windows XP
PHP Version: 5.3.1
New Comment:
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.
Previous Comments:
------------------------------------------------------------------------
[2009-12-12 22:19:44] j...@php.net
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..?
------------------------------------------------------------------------
[2009-12-12 21:54:29] pcdinh at gmail dot com
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
------------------------------------------------------------------------
[2009-12-12 21:41:44] pcdinh at gmail dot com
Description:
------------
mysqli_more_results() will always return false after
mysqli_multi_query() for both SELECT and non SELECT queries
Therefore I can not use the loop while (mysqli_more_results()) in
combination with mysqli_next_result() to iterate through result sets
produced by SELECT queries
mysqli_multi_query($conn, $query);
while (mysqli_more_results($conn))
{
mysqli_next_result($query);
/* store first result set */
if ($result = mysqli_store_result($conn)) {
}
}
Code example in http://php.net/manual/en/mysqli.multi-query.php is
outdated because it causes E_STRICT in PHP 5.3.1. It requires
mysqli_more_results() to be called before mysqli_next_result()
There is a workaround
if (mysqli_multi_query($link, $query)) {
do {
/* store first result set */
if ($result = mysqli_store_result($link)) {
while ($row = mysqli_fetch_row($result)) {
printf("%s\n", $row[0]);
}
mysqli_free_result($result);
}
// print divider => will never work
if (mysqli_more_results($link)) {
printf("-----------------\n");
}
} while (mysqli_more_results($link) && mysqli_next_result($link));
}
but mysqli_more_results() seems to do nothing related to result sets
here
Reproduce code:
---------------
<?php
$link = mysqli_connect("localhost", "root", "123456", "test");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT 1";
/* execute multi query */
if (mysqli_multi_query($link, $query)) {
var_dump(mysqli_more_results($link));
}
/* close connection */
mysqli_close($link);
?>
Expected result:
----------------
bool(true)
Actual result:
--------------
bool(false)
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=50462&edit=1
