Your code seems very badly organized if you can really mix into a single line of execution like that. You might look at refactoring the design. That said, caching the cached statements yourself is trivial with Perl–

my %query_map; # Actually declared in higher (more outer) scope.
if ( $x > 10 ) {
    $query = "SELECT Name FROM Customers WHERE CustId = ?";
}
else {
    $query = "SELECT Name FROM Sales WHERE SalesId = ?";
}
$query_map{$query} ||= $dbh->prepare($query);

$query_map{$query}->execute(@args_that_will_match_query);
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