...
my $query = qq{
select * from blah_table where col1 = :p0
  union select * from blah_table where col1 = :p0
    union select * from blah_table where col1 = :p1
      union select * from blah_table where col1 = :p0
        union select * from blah_table where col1 = :p1
  };

...
my @args = ('foo_param0', 'foo_param1');
...