-- 為tdb_goods_types添加child_count字段

? ALTER TABLE tdb_goods_types ADD child_count MEDIUMINT UNSIGNED NOT NULL DEFAULT 0;

-- 將剛才查詢到的子類數量更新到tdb_goods_types數據表

? UPDATE tdb_goods_types AS t1 INNER JOIN ( SELECT p.type_id,p.type_name,count(s.type_name) AS children_count FROM tdb_goods_types AS p?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? LEFT JOIN tdb_goods_types AS s ON s.parent_id = p.type_id?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? GROUP BY p.type_name?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ORDER BY p.type_id ) AS t2?

? ON ?t1.type_id = t2.type_id?

? SET t1.child_count = t2.children_count;

-- 復制編號為12,20的兩條記錄

? SELECT * FROM tdb_goods WHERE goods_id IN (19,20);

-- INSERT ... SELECT實現復制

? INSERT tdb_goods(goods_name,cate_id,brand_id) SELECT goods_name,cate_id,brand_id FROM tdb_goods WHERE goods_id IN (19,20);

-- 查找重復記錄

? SELECT goods_id,goods_name FROM tdb_goods GROUP BY goods_name HAVING count(goods_name) >= 2;