我有一個問題,我無法從我的MySQL數據庫(通過PHP)檢索結果。我在其他地方使用相同的功能,並且工作完美無瑕。然而,在這一點上,我不斷收到「警告:mysqli_query():無法獲取mysqli」錯誤。下面解釋了這個問題的細節。 我用一個非常類似的功能在別處(getAllCountries如下圖所示),在我的PHP這也很好地工作:警告:mysqli_query():無法獲取mysqli
function getAllCountries()
{
$result = db_query("SELECT countryid, name FROM country ORDER BY name ASC");
echo "<select class=addresscountry name=country>";
while($row = mysqli_fetch_array($result)) {
echo '<option value="' . $row['countryid'] . '">' . $row['name'] . '</option>';
}
echo "</select>";
mysqli_close(db_connect());
}
所以問題是:
我有一個包含以下代碼的PHP文件:
<?php
require 'includes/functions.php';
function getUserPicPath()
{
$userid = $_SESSION['userid'];
$result = db_query("SELECT picture FROM user WHERE userid='$userid'");
while($row = mysqli_fetch_array($result)) {
$picturepath = $row['picture'];
}
echo $picturepath;
mysqli_close(db_connect());
}
我functions.php文件具有以下行(與其他不相關的功能整合在一起):
require 'dbfunctions.php';
和我dbfunctions.php看起來是這樣的:
<?php
function db_connect()
{
require ".db_password.php";
static $connection;
if(!isset($connection)) {
$connection = mysqli_connect('localhost',$username,$password,$dbname);
}
if($connection === false) {
return mysqli_connect_error();
}
return $connection;
}
function db_query($query)
{
$connection = db_connect();
$result = mysqli_query($connection,$query);
return $result;
}
在我的PHP文件我調用下面的函數:
if ($userid == -1)
{
showNotAuthorizedPage();
} else {
myAccountPage();
}
和myAccountPage()函數在同一個文件中聲明getUserPicPath()函數,此getUserPicPath()函數被調用如下:
<div id="tabs-2">
<p><?php getUserPicPath(); ?></p>
</div>
我使用標籤(http://jqueryui.com/tabs/#default)在我的網頁,這就是我想要的調用它 的myAccountPage()函數,它提供了以下錯誤:
Warning: mysqli_query(): Couldn't fetch mysqli in C:\Users\Dennis\Documents\My Dropbox\xxx\zzz\www\Project Files\includes\dbfunctions.php on line 29
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}() ..\myaccount.php:0
2 0.0010 283328 myAccountPage() ..\myaccount.php:181
3 0.0070 285368 getUserPicPath() ..\myaccount.php:121
4 0.0070 285528 db_query() ..\myaccount.php:11
5 0.0070 285624 mysqli_query () ..\dbfunctions.php:29
(!) Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, null given in C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php on line 13
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}() ..\myaccount.php:0
2 0.0010 283328 myAccountPage() ..\myaccount.php:181
3 0.0070 285368 getUserPicPath() ..\myaccount.php:121
4 0.0080 285768 mysqli_fetch_array () ..\myaccount.php:13
(!) Notice: Undefined variable: picturepath in C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php on line 17
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}() ..\myaccount.php:0
2 0.0010 283328 myAccountPage() ..\myaccount.php:181
3 0.0070 285368 getUserPicPath() ..\myaccount.php:121
(!) Warning: mysqli_close(): Couldn't fetch mysqli in C:\Users\Dennis\Documents\My Dropbox\me&roxy\WE\final project\Project Files\myaccount.php on line 19
Call Stack
# Time Memory Function Location
1 0.0000 256880 {main}() ..\myaccount.php:0
2 0.0010 283328 myAccountPage() ..\myaccount.php:181
3 0.0070 285368 getUserPicPath() ..\myaccount.php:121
4 0.0100 285864 mysqli_close () ..\myaccount.php:19
這不是完整的信息。就像你檢查連接錯誤一樣,你也應該檢查查詢錯誤。我對mysqli不熟悉,但是如果你打開這個手冊,你會發現它的名字上有'error'錯誤。 –
爲什麼在'getUserPicPath()'中運行查詢兩次?第一次通話後的「回聲」會給你什麼? – andrewsi
我還建議檢查一下'mysqli_error()'裏面的內容,這樣你就可以看到數據庫傳回的錯誤 – andrewsi