thinkphp子查询

$product_info = M('product_info as info');

$productinfo = $product_info->join('left join c_price_comment as comment on info.sku=comment.sku')->where($where)->order('info.create_time desc')->field('info.*,comment.comment_count')->buildSql();

$list = M()->table($productinfo.' a')->order(' '.$order.'')->group('sku ')->limit($limit)->select();