PHP警告mysql_fetch_assoc [英] php warning mysql_fetch_assoc
问题描述
我正在尝试从mysql访问某些信息,但收到警告:mysql_fetch_assoc():对于下面的第二行代码,提供的参数不是有效的MySQL结果资源,对您的帮助将不胜感激.
I am trying to access some information from mysql, but am getting the warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource for the second line of code below, any help would be much appreciated.
$musicfiles=getmusicfiles($records['m_id']);
$mus=mysql_fetch_assoc($musicfiles);
for($j=0;$j<2;$j++)
{
if(file_exists($mus['musicpath']))
{
echo '<a href="'.$mus['musicpath'].'">'.$mus['musicname'].'</a>';
}
else
{
echo 'Hello world';
}
}
function getmusicfiles($m_id)
{
$music="select * from music WHERE itemid=".$s_id;
$result=getQuery($music,$l);
return $result;
}
推荐答案
通常,mysql_ *函数的用法如下:
Generally, the mysql_* functions are used as follows:
$id = 1234;
$query = 'SELECT name, genre FROM sometable WHERE id=' . $id;
// $query is a string with the MySQL query
$resource = mysql_query($query);
// $resource is a *MySQL result resource* - a mere link to the result set
while ($row = mysql_fetch_assoc($resource)) {
// $row is an associative array from the result set
print_r($row);
// do something with $row
}
如果您将不是MySQL结果资源的内容传递给mysql_fetch_assoc(无论它是字符串,对象还是布尔值),则该函数将抱怨它不知道如何处理该参数;正是您所看到的.
If you pass something to mysql_fetch_assoc that is not a MySQL result resource (whether it's a string, an object, or a boolean), the function will complain that it doesn't know what to do with the parameter; which is exactly what you are seeing.
常见问题:如果将某些内容(不是有效的查询字符串)传递给mysql_query
,则会收到此警告:
A common gotcha: you get this warning if you pass something (other than a valid query string) to mysql_query
:
$id = null;
$query = 'SELECT name, genre FROM sometable WHERE id=' . $id;
$res = mysql_query($query);
// $res === FALSE because the query was invalid
// ( "SELECT name, genre FROM sometable WHERE id=" is not a valid query )
mysql_fetch_assoc($res);
// Warning: don't know what to do with FALSE, as it's not a MySQL result resource
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