显示适当的余额，按降序显示MySQL行

Question

I have a query that is supposed to show deposits, withdrawls, and balance. I am summing the deposits and withdrawls to get the balance.

The query and display works ok when ORDER BY date ASC.

However, I wish to order by DESC and this is causing issues with the display of balance. Here is an example.

Date   Deposit   Withdrawl   Balance
Jan 2            $2000       -$2000
Jan 1  $5000                 $3000

As you can see I would want the Jan 1 balance to be 5000 and the Jan 2 balance to be 3000. I'm stuck on a good way to solve this. At first, I simply created a column for balance and inserted the balance as the row was being written. But this caused problems when a single row was updated.

Any help appreciated! Thanks.

Here is the code I'm working with.

$result2 = mysql_query("SELECT * FROM bankaccount_transaction WHERE bankaccount_id = '$id' ORDER BY ID DESC ".$pages->get_limit()) or die(mysql_error());

while($row2 = mysql_fetch_array($result2)) {
$date = date('m-d-Y', strtotime($row2['date']));

if ($row2['deposit'] > 0){
$deposit = $row2['deposit'];
$newdeposit = number_format($deposit,2);
$newtotal += $deposit;
}else{
$newdeposit = '';
}

if ($row2['withdrawl'] > 0){
$withdrawl = $row2['withdrawl'];
$newwithdrawl = number_format($withdrawl,2);
$newtotal -= $withdrawl;
}else{
$newwithdrawl = '';
}

display table

}

Answer 1

SELECT x.*
     , SUM(y.deposit)-SUM(y.withdrawal) Balance 
  FROM transactions x 
  JOIN transactions y 
    ON y.bankaccount_id = x.bankaccount_id
   AND y.date <= x.date
 WHERE x.bankaccount_id='$id' 
 GROUP 
    BY x.date 
 ORDER 
    BY Date DESC;

Here's a fiddle