PDO事务中受影响记录的计数

Question

I have a script that runs a pretty basic PDO transaction and it doe work (selects records and performs the merge based on those results)

So it successfully inserts/updates but I'm trying to get a count of accurate records and it doesn't work, it just returns 1 in powershell.

Starting with an empty database table and running this script, It inserts 1300 records successfully but $count prints '1'. I'm simply trying to get record counts, success messages and errors for the purpose of an email when the script runs. Am I missing something?

while($arr = odbc_fetch_array($result)){

    $stmt = $PDO->prepare("
        MERGE INTO ORDER_STATUS as S
            USING (VALUES(
                        CAST(:ORDER_ID as INT),
                        CAST(:ORDER_STATUS as VARCHAR(45)),
                        CAST(:is_active as DECIMAL(1,0)),
                        CAST(:DATE_UPDATED as DATE)
                        )
                    )
            AS O(order_id, order_status, is_active, date_updated)    
            ON O.order_id = S.order_id  
        WHEN MATCHED THEN UPDATE SET order_status = O.order_status, is_active = O.is_active, date_updated = O.date_updated
        WHEN NOT MATCHED THEN INSERT(order_id,order_status,is_active,date_updated) VALUES(O.order_id, O.order_status, O.is_active, O.date_updated)
    ");

    $PDO->beginTransaction();
    $i = 0;
    while($db2row = odbc_fetch_array($result)) {

        if(++$i % 1000 == 0) {
            $PDO->commit();
            $PDO->beginTransaction();
        }
        $stmt->execute($db2row);
    }
    $PDO->commit();
    $count = $stmt->rowCount();
    print_r($count);
}