【电商网站】将select查询出来的结果集作为一个表

1.这种方式的联合查询：

/** * 通过order_id 获取某个订单的所有商品 * @param int $order_id * @return array */public function get_order_product($order_id, $param=1) {if (empty($order_id)) {return;}if ($param == 1) {$sql = "SELECT g.*, d.brand_name, d.brand_id, b.mini FROM (SELECT a.*FROM " . TBL_PRE . "orders_item a WHERE a.order_id = '{$order_id}') AS g  LEFT JOIN " . TBL_PRE . "products_images b ON g.product_id = b.product_id AND b.is_default = 1LEFT JOIN " . TBL_PRE . "products e ON g.product_id = e.product_id LEFT JOIN " . TBL_PRE . "goods c ON c.goods_id = e.goods_id LEFT JOIN " . TBL_PRE . "goods_brand d ON d.brand_id = c.brand_id";} elseif ($param == 2) {$sql = "SELECT * FROM " . TBL_PRE . "orders_item WHERE order_sn = '{$order_id}'" ;}return $this->db->get_all($sql);}

2.

/** * 初始化购物车 */public function init_minicart ($member_id) {if ( empty($member_id) ) {return;}$sql = "SELECT a.*, b.price, c.product_name, c.product_id, d.mini, f.brand_name, f.brand_id  FROM ( SELECT * FROM " . TBL_PRE . "cart WHERE member_id = '{$member_id}' ) AS a LEFT JOIN " . TBL_PRE . "product_spec b ON a.product_spec_id = b.product_spec_id LEFT JOIN " . TBL_PRE . "products c ON b.product_id = c.product_id LEFT JOIN " . TBL_PRE . "products_images d ON b.product_id = d.product_id AND d.is_default = 1 LEFT JOIN " . TBL_PRE . "goods e ON e.goods_id = c.goods_id LEFT JOIN " . TBL_PRE . "goods_brand f ON f.brand_id = e.brand_id";$cart = $this->db->get_all($sql);return $cart;}

3.

/** * 获得我的收藏夹 * @param $member_id */function get_my_collec( $member_id, $page, $page_count ) {if ( empty($member_id) ) {return array();}$sql_collec = "SELECT * FROM " . TBL_PRE . "member_collection WHERE member_id = '{$member_id}' ORDER BY create_time DESC";if ( !empty($page) && !empty($page_count) ) {$page_start = (max(1,$page)-1)*$page_count;$sql_collec .= " LIMIT {$page_start},{$page_count}";}$collec_list = $this->db->get_all($sql_collec);if ( empty($collec_list) ) {return;}

                return $collec_list;

        }