一、语法
| {EXPLAIN | DESCRIBE | DESC} tbl_name [col_name | wild] {EXPLAIN | DESCRIBE | DESC} [explain_type] SELECT select_options explain_type: {EXTENDED | PARTITIONS} |
二、数据库准备
表一：
| DROP TABLE IF EXISTS `products`;SET @saved_cs_client = @@character_set_client;SET character_set_client = utf8;CREATE TABLE `products` ( `products_id` int(11) unsigned NOT NULL auto_increment, `products_type` int(11) unsigned NOT NULL default '1', `products_quantity` float NOT NULL default '0', `products_model` varchar(32) default NULL, `products_upc` varchar(32) default NULL, `products_isbn` varchar(32) default NULL, `products_image` varchar(128) default NULL, `products_image_thumbnail` varchar(200) NOT NULL， `products_price` decimal(15,4) NOT NULL default '0.0000', `products_virtual` tinyint(1) NOT NULL default '0', `products_date_added` datetime NOT NULL default '0001-01-01 00:00:00', `products_last_modified` datetime default NULL, `products_date_available` datetime default NULL, `products_weight` float NOT NULL default '0', `products_status` tinyint(1) NOT NULL default '0', `products_tax_class_id` int(11) NOT NULL default '0', `manufacturers_id` int(11) default NULL, `products_web_id` int(11) default NULL, `products_ordered` float NOT NULL default '0', `products_quantity_order_min` float NOT NULL default '1', `products_quantity_order_units` float NOT NULL default '1', `products_priced_by_attribute` tinyint(1) NOT NULL default '0', `product_is_free` tinyint(1) NOT NULL default '0', `product_is_call` tinyint(1) NOT NULL default '0', `products_quantity_mixed` tinyint(1) NOT NULL default '0', `product_is_always_free_shipping` tinyint(1) NOT NULL default '0', `products_qty_box_status` tinyint(1) NOT NULL default '1', `products_quantity_order_max` float NOT NULL default '0', `products_sort_order` int(11) NOT NULL default '0', `products_discount_type` tinyint(1) NOT NULL default '0', `products_discount_type_from` tinyint(1) NOT NULL default '0', `products_price_sorter` decimal(15,4) NOT NULL default '0.0000', `master_categories_id` int(11) NOT NULL default '0', `products_mixed_discount_quantity` tinyint(1) NOT NULL default '1', `metatags_title_status` tinyint(1) NOT NULL default '0', `metatags_products_name_status` tinyint(1) NOT NULL default '0', `metatags_model_status` tinyint(1) NOT NULL default '0', `metatags_price_status` tinyint(1) NOT NULL default '0', `metatags_title_tagline_status` tinyint(1) NOT NULL default '0', `itemno` varchar(32) default NULL, `products_images_no` varchar(10) default '0', `products_url` varchar(512) default NULL, PRIMARY KEY (`products_id`), UNIQUE KEY `itemno` (`itemno`)) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;SET character_set_client = @saved_cs_client; |
表二：
| DROP TABLE IF EXISTS `products_image`;SET @saved_cs_client = @@character_set_client;SET character_set_client = utf8;CREATE TABLE `products_image` ( `id` int(10) unsigned NOT NULL auto_increment, `products_id` int(10) unsigned NOT NULL, `products_images_no` varchar(10) default '0'， `image_dir` varchar(200) default NULL, `products_image_thumbnail` varchar(200) default NULL， `flag` int(2) default NULL, `up_time` datetime default NULL, `web_from` varchar(20) default NULL, PRIMARY KEY (`id`), KEY `idx_porducts_id` (`products_id`)) ENGINE=MyISAM AUTO_INCREMENT=1DEFAULT CHARSET=utf8;SET character_set_client = @saved_cs_client; |
