PDO加入不显示任何内容

Question

PDO is not displaying any data could somebody help me out:

$ClanData_users = sql::db()->prepare('SELECT * FROM clan_game INNER JOIN clan_page ON clan_game.clan_home = clan_page.id ORDER BY clan_game.date ASC');
$ClanData_users->execute();
$q = ($ClanData_users);

$content .= '<table class="forum"><tbody><tr class="bericht-content"><td> Kalender</td></tr>';
while($r = $q->fetch()){
    $content .= '<tr><td><span class="beschrijving"><p> '.$r['clan_game.clan_home'].' '.$r['clan_challenger'].' '.ucfirst(strftime("%A %H <b>%B</b> %Y | %R", strtotime($r['date']))).'  </p></span></td></tr> ';
}
$content .= '</tbody></table>';

Answer 1

It usually isn't a good idea to SELECT * in a JOIN query. Instead, be specific about the columns you need, and assign aliases to them when the names overlap. You cannot access them with the table name via $r['table_name.column_name'] after fetching. The associative columns will only be available in $r['column_name'] by the column name or alias, so all column names/aliases must be unique.

$ClanData_users = sql::db()->prepare('
  SELECT 
    /* If both tables have the same column name, use an alias */
    clan_game.id AS clan_game_id,
    clan_home.id AS clan_home_id,
    clan_game.clan_home AS clan_home,
    clan_challenger,
    /* etc... Be specific and alias as necessary */
  FROM clan_game 
    INNER JOIN clan_page ON clan_game.clan_home = clan_page.id
  ORDER BY clan_game.date ASC');

When fetching, use only the column name or alias

// Why reference $ClanData_users as $q here? That's confusing. Just fetch from $ClanData_users
while($r = $ClanData_users->fetch(PDO::FETCH_ASSOC)){
    $content .= '<tr><td><span class="beschrijving"><p> '.$r['clan_home'].' '.$r['clan_challenger'].' '.ucfirst(strftime("%A %H <b>%B</b> %Y | %R", strtotime($r['date']))).'  </p></span></td></tr> ';
}