I think that seeing more of the actual code would be helpful. The question is, why is your DBD::CSV::Statement object not a valid SQL::Statement object?

It may be that $query contains some metacharacter that is causing problems. Using either $dbh->quote() or placeholders will avoid this problem: my $sql = "select title from $TABLE2 where astype like " . $dbh->quote("%$query"); I generally prefer using placeholders:

my $sql = "select title from $TABLE2 where astype like ?";
my $sth = $dbh->prepare($sql) or die "Cannot prepare: " . $dbh->errstr
+();
$sth->execute("%$query") or die "Cannot execute: " . $sth->errstr();
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Note that, if you use a placeholder, the placeholder must substitute for the entire string being matched, including any wildcards.

P.S. $ and @ interpolate in double-quoted strings, but % does not.