如果mysql_num_rows等于0则不起作用

Question

I'm using this code to count rows and trying to do IF num rows equals to ZERO do INSERT if not UPDATE but it doesn't work.

When I use == operator nothing happens. If I use >= operator script inserting the values but running insert query on every refresh and values are duplicating in MySQL table.

Here is the code:

$isexist = mysql_query("select count(*) from wcddl_filehosts where downloadid = '".$download[id]."'");

if (mysql_num_rows($isexist) == 0) {
mysql_query("insert into wcddl_filehosts (downloadid, rs) values ('".$download[id]."','$totalRS')");
} else {
mysql_query("update wcddl_filehosts set rs = '$totalRS' where downloadid = '".$download[id]."'");
}

What's wrong with this?

Answer 1

Count will return a value, and you cannot count and then call mysql_num_rows. It is either one of the other.

You could do

$isExist = mysql_query("Select count(id) from ..."); 
$r = mysql_fetch_array($isExist);
if($r['COUNT(id)'] > 0){
//item exists
}else{
//item doesnt exist
}

If alternatively you can do the query as:

$isexist = mysql_query("select * from wcddl_filehosts where downloadid = '".$download[id]."'");
if(mysql_num_rows($isExists)>0){
//we have items
}else{
//we dont have items
}