If you want this literal string of eight characters - $in{cid} - to be the value being tested in the where clause, you could do it like this:

my $dbh = DBI->connect( $whatever… )
...
my $sth = $dbh->prepare( "select field from table where id != ?" );
$sth->execute( '$in{cid}' );  # an 8-character string is the placehold
+er value
...
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my %in;
$in{cid} = "something";

my $dbh = DBI->connect( $whatever… )
...
my $sth = $dbh->prepare( "select field from table where id != ?" );
$sth->execute( $in{cid} );  # the hash element value is the placeholde
+r value
...
[download]