I would suggest: 
my $updateDeduct = $DBH->prepare("UPDATE USER SET BALANCE = BALANCE - 
+? WHERE USERNAME = ?");
my $updateAdd = $DBH->prepare("UPDATE USER SET BALANCE = BALANCE + ? W
+HERE USERNAME = ?");

$DBH->do("BEGIN");  #  explicitly start a new transaction
                    #  this overrides autocommit setting

$updateDeduct->execute($amount, $user);
$updateAdd=>execute($amount, $user);

$DBH->do("COMMIT");  #end transaction, this is the "expensive part" ti
+mewise

[download]
In general, don't put prepare statements inside of a loop. You can prepare once and use many times.

In reply to Re: run 2 query mysql by Marshall
in thread run 2 query mysql by bigup401

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