protected function copyContent(Schema $schema)
    {
        $num = $this->connection->fetchAssoc('SELECT COUNT(*) FROM plg_feature_page');

        $id = 1;
        for ($i=1; $i<=$num; $i++) {
            $this->addSql("INSERT INTO plg_feature_content (feature_id, position, content) SELECT id, 1, content1 FROM plg_feature_page WHERE id=".$i.";");
            $this->addSql("INSERT INTO plg_feature_content (feature_id, position, content) SELECT id, 2, content2 FROM plg_feature_page WHERE id=".$i.";");
            $this->addSql("INSERT INTO plg_feature_content (feature_id, position, content) SELECT id, 3, content3 FROM plg_feature_page WHERE id=".$i.";");
            $this->addSql("INSERT INTO plg_feature_content (feature_id, position, content) SELECT id, 4, content4 FROM plg_feature_page WHERE id=".$i.";");    // ★ ここでエラー発生
            $this->addSql("INSERT INTO plg_feature_content (feature_id, position, content) SELECT id, 5, content5 FROM plg_feature_page WHERE id=".$i.";");
        }
    }