my ( $query, @args );
if ( $x > 10 ) {
    $query = 'select Name from Customers where CustID = ?';
    @args = ( $custid );
} else {
    $query = 'select Name from Sales where SalesId = ? and CustID = ?'
+;
    @args = ( $salesid, $custid );
}

my $sth = $dbh->prepare( $query );
$sth->execute( @args );
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