$yesterday = array ( 
    \'year\' => date(\'y\'), 
    \'month\' => date(\'m\'), 
    \'day\' => date(\'d\')-1 
);

$rows = $wpdb->query($wpdb->prepare(*emphasized text*
    "SELECT id, yymmdd 
    FROM plugin_data 
    WHERE yymmdd LIKE \'%d-%d-%d", 
    $yesterday[\'year\'], $yesterday[\'month\'], $yesterday[\'day\']
));

foreach ( $rows as $r ) {
    $id_for_yesterday_rows[]= $r->id;
}