my $get_amt = $dbh->prepare( qq{SELECT SUM(amount) FROM `pot` WHERE
   `apdid`=? AND `status`='preissue'} );

my $upd_pay = $dbh->prepare( qq{UPDATE `pot` SET `status`='issued',
   `checkno`=?,statuschanged=? WHERE `apdid`=? AND `status`='preissue'} );

my @file_fields = qw/checkNo checkAmt empID payDate/;

while ( my $_line = <IN> ) {  # assuming lines are coming from a file
    my %lineData = ();
    @lineData{@file_fields} = split /,/, $_line;

    $get_amt->execute( $lineData{empID} );
    my $rows = $get_amt->fetchall_arrayref;
    my $sum = 0;
    for my $row ( @$rows ) {
        my ( $amt ) = @$row;
        $sum += $amt;
    }
    if ( $sum != $lineData{checkAmt} ) {
        warn sprintf( "empID %s: mismatch: sum of preissue rows= %s, checkAmt= %s\n",
            $lineData{empID}, $sum, $lineData{checkAmt} );
        next;
    }
    $upd_pay->execute( $lineData{checkNo}, $lineData{payDate}, $lineData{empID} );
}