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my @param = <array of values to pass TO database>;
my $sql = <some SQL with placeholders = ? to take values>;
my $array_ref = $dbh->selectall_arrayref($sql,undef,@param);

my $dbh = <create database handle>;
my $sth = $dbh->prepare("select * from table where col1=? and col2=?")
+;
...
@param = ("test2a","test2b);
$array_ref = $sth->selectall_arrayref($sth,undef,@param);
...