use DBI;
use Data::Dumper;

my $dbh = DBI->connect(
		       'DBI:mysql:database=test;host=localhost', 
		       'test', 
		       'test',
		       { RaiseError => 1 }
		       );

sub init
{
  # $dbh->do("DROP TABLE t;");
  $dbh->do("CREATE TABLE t (id INT, x INT, name CHAR(2));");
  $dbh->do("INSERT INTO t (id, x, name) VALUES (1, 0, 'a'), (2, 1, 'b'), (3, 1, 'c'), (4, 2, 'd');");
}


sub doit
{
  my ($cols) = @_;

  my $COLS = join(', ', @$cols);
  my $sql = "SELECT $COLS FROM t AS a, t AS b WHERE a.name = 'b' AND b.name = 'c' AND a.x = b.x";
  my $sth = $dbh->prepare($sql);

  my $rv = $sth->execute();

  my $results = $sth->fetchall_arrayref({});

  print Data::Dumper->new([ $sql, $results ], [qw( $sql $results)])->Dump(), "\n";
}


init();

doit(['*']);
doit(['a.*', 'b.*']);
doit(['a.id', 'a.x', 'a.name', 'b.id', 'b.x', 'b.name']);

1;