$sql = "SELECT DISTINCT r.itemID, r2.ratingValue - r.ratingValue
as rating_difference
FROM rating r, rating r2
WHERE r.userID=$userID AND
r2.itemID=$itemID AND
r2.userID=$userID;";
$db_result = mysql_query($sql, $connection);
$num_rows = mysql_num_rows($db_result);
while ($row = mysql_fetch_assoc($db_result)) {
$other_itemID = $row["itemID"];
$rating_difference = $row["rating_difference"];
if (mysql_num_rows(mysql_query("SELECT itemID1
FROM dev WHERE itemID1=$itemID AND itemID2=$other_itemID",
$connection)) > 0) {
$sql = "UPDATE dev SET count=count+1,
sum=sum+$rating_difference WHERE itemID1=$itemID
AND itemID2=$other_itemID";
mysql_query($sql, $connection);
if ($itemID != $other_itemID) {
$sql = "UPDATE dev SET count=count+1,
sum=sum-$rating_difference
WHERE (itemID1=$other_itemID AND itemID2=$itemID)";
mysql_query($sql, $connection);
}
}
答案 0 :(得分:-1)
你没有连接任何数据库使用像这样的东西
$link = mysql_connect('dbhost', 'dbusername', 'dbpassword');
$connection = mysql_select_db('tablename', $link);