MySQL用php变量麻烦

I'm having trouble with putting a php variable into a mysql query.

For example:

mysql_query("SELECT * FROM listings WHERE title LIKE '%ipod%'");

That works, but

$key = "ipod";
mysql_query("SELECT * FROM listings WHERE title LIKE '%$key%'");

That doesn't work.

I might be doing it wrong though. If the above is the correct way to do it, then maybe another part of my script has a typo or something like that. Any help would be great.

Your not selecting anything:

"SELECT * FROM listings WHERE title LIKE '%$key%'"

notice the *

Try this:

$key = "ipod";
$results = mysql_query("SELECT * FROM listings WHERE title LIKE '$key'");
$num = mysql_num_rows($results);
echo "Received " . $num . "rows of results";

While ($row = mysql_fetch_assoc($results)) {
    echo '<pre>';
    print_r($row);
    echo '</pre>';
}

$key = "ipod";
mysql_query("SELECT * FROM listings WHERE title LIKE '".$key."'");

Try this:

 $key = "ipod";
 mysql_query("SELECT * FROM listings WHERE title LIKE '%".$key."%'");