Check in MySQL table if my ID exist in the results - mysql

Question

How to check in MySQL table if my ID exist in the results and return TRUE, but this is a little complicated as I would like to check GROUP of records and not the last one from that GROUP, code below for the table and query which doesn't work, I would like to check if my $session_user_id exist in the GROUP OF auction_bid_item_id but not check last row as the last row is a WINNING ROW.
CREATE TABLE `auction_bids` (
`auction_bid_id` int(11) NOT NULL AUTO_INCREMENT,
`auction_bid_user_id` int(11) NOT NULL,
`auction_bid_seller_id` int(11) NOT NULL,
`auction_bid_item_id` int(11) NOT NULL,
PRIMARY KEY (`auction_bid_id`)
);
MySQL Query:
SELECT * FROM auction_bids
WHERE auction_bid_user_id = '$session_user_id'
GROUP BY auction_bid_item_id;

Answer 1

Join against a subselect which determines if the user is in that group.
Ie, the following will get you the bids and a field saying if the user is found.
SELECT auction_bids.*, IF(Sub1.auction_bid_item_id IS NULL, 'User not found', 'User found')
FROM auction_bids
LEFT OUTER JOIN
(
SELECT DISTINCT auction_bid_item_id
FROM auction_bids
WHERE auction_bid_user_id = '$session_user_id'
) Sub1
ON auction_bids.auction_bid_item_id = Sub1.auction_bid_item_id
GROUP BY auction_bids.auction_bid_item_id
EDIT - try this to try and ignore the latest bid
SELECT auction_bids.*, IF(Sub1.auction_bid_item_id IS NULL, 'User not found', 'User found')
FROM auction_bids
LEFT OUTER JOIN
(
SELECT DISTINCT auction_bids.auction_bid_item_id
FROM auction_bids
LEFT OUTER JOIN
(
SELECT auction_bid_item_id, MAX(auction_bid_id) AS LastBid
FROM auction_bids
GROUP BY auction_bid_item_id
) Sub2
ON auction_bids.auction_bid_item_id = Sub2.auction_bid_item_id
AND auction_bids.auction_bid_id = Sub2.LastBid
WHERE Sub2.auction_bid_item_id IS NULL
AND auction_bid_user_id = '$session_user_id'
) Sub1
ON auction_bids.auction_bid_item_id = Sub1.auction_bid_item_id
GROUP BY auction_bids.auction_bid_item_id

Answer 2

Something like this? (with php)
$id_exists = false;
$id = mysql_real_escape_string($_GET['id']);
$select = "SELECT auction_bid_id FROM auction_bids WHERE auction_bid_id ='$id'";
$result = mysql_query($select);
if(mysql_num_rows($result) > 0){
$id_exists = true;
}else{
$id_exists = false;
}