Perl DBI-绑定列表

Question

How do I bind a variable to a SQL set for an IN query in Perl DBI?

Example:

my @nature = ('TYPE1','TYPE2'); # This is normally populated from elsewhere
my $qh = $dbh->prepare(
      "SELECT count(ref_no) FROM fm_fault WHERE nature IN ?"
) || die("Failed to prepare query: $DBI::errstr");

# Using the array here only takes the first entry in this example, using a array ref gives no result
# bind_param and named bind variables gives similar results
$qh->execute(@nature) || die("Failed to execute query: $DBI::errstr");

print $qh->fetchrow_array();

The result for the code as above results in only the count for TYPE1 , while the required output is the sum of the count for TYPE1 and TYPE2 . Replacing the bind entry with a reference to @nature ( \\@nature ), results in 0 results.

The main use-case for this is to allow a user to check multiple options using something like a checkbox group and it is to return all the results. A work-around is to construct a string to insert into the query - it works, however it needs a whole lot of filtering to avoid SQL injection issues and it is ugly...

In my case, the database is Oracle, ideally I want a generic solution that isn't affected by the database.

Answer 1

There should be as many ? placeholders as there is elements in @nature , ie. in (?,?,..)

my @nature = ('TYPE1','TYPE2');
my $pholders = join ",", ("?") x @nature;
my $qh = $dbh->prepare(
    "SELECT count(ref_no) FROM fm_fault WHERE nature IN ($pholders)"
) or die("Failed to prepare query: $DBI::errstr");