If else statement with mysql table? - PHP - php

Question

I need to make an if else statement that will prevent a user from bidding on an item if they are the highest bidder. I think it would go a little something like this.
if ($accountid = the accountid in the bidhistory table)
{
echo "You are the highest bidder!";
}
else
{
$sql="INSERT INTO bidhistory (accountid, biditemid)
VALUES ($accountid, $itemid)";
mysql_query("
UPDATE bidhistory
SET bidprice = bidprice + 1
WHERE biditemid = " .
#mysql_escape_string($itemid));
$result=mysql_query($sql) or die("Error in adding bid for item: ".mysql_error());
}
?>
I'm not sure how to reference the accountid from the bidhistory table. Also, if there is a better way to do this, please point me in the wright direction. Thanks!

Answer 1

Note:
You can fetch the row of the highest bid with the specific item first.
Then check if the highest bidder (accountid) is the same with the current user.
You can check the notes I had for some lines quoted in /* ... */
Your query for checking:
$result = mysql_query("SELECT accountid FROM bidhistory WHERE biditem = '$itemid' ORDER BY bidhistoryid DESC LIMIT 1"); /* GET THE LAST ROW FOR WHO BIDS LAST; AND REPLACE NECESSARY COLUMN NAME (unique/primary) - bidhistoryid */
while($row = mysql_fetch_array($result)){
$checkaccountid = $row['accountid']; /* STORE THE USER THAT BIDS LAST FOR THIS ITEM */
}
if($checkaccountid == $accountid){ /* THEN COMPARE IT WITH THE CURRENT USER */
/* CODE YOU WANT TO DO IF HE/SHE IS THE LAST BIDDER ALREADY */
}
else {
/* IF NOT, HE/SHE CAN STILL BID */
}
But I recommend that you use mysqli_* rather than the deprecated mysql_* API.
$con = new mysqli("YourHost", "Username", "Password", "Database"); /* REPLACE NECESSARY DATA */
/* CHECK CONNECTION */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if($stmt = $con->prepare("SELECT accountid FROM bidhistory WHERE biditem = ? ORDER BY bidhistoryid DESC LIMIT 1")){
$stmt->bind_param("i",$itemid); /* BIND THIS VARIABLE TO YOUR QUERY ABOVE */
$stmt->execute(); /* EXECUTE THE QUERY */
$stmt->bind_result($checkaccountid); /* STORE THE RESULT TO THIS VARIABLE */
$stmt->fetch(); /* FETCH THE RESULT */
if($checkaccountid == $accountid){
/* CODE YOU WANT TO DO IF HE/SHE IS THE LAST BIDDER ALREADY */
}
else {
/* IF NOT, HE/SHE CAN STILL BID */
}
$stmt->close();
} /* END OF PREPARED STATEMENT */