SELECT s.type_id,s.type_name,p.type_name FROM tdb_goods_types AS s LEFT JOIN tdb_goods_types AS p ON s.parent_id = p.type_id;
报错 ERROR 1054 (42S22): Unknown column 's.type_id' in 'field list'
视频教程非常好！学到了很多，刚刚看视频想到一个操作，结果出错了，然后自己接着看就解决了！SELECT goods_id,goods_name,goods_cate,brand_name,goods_price FROM tdb_goods WHERE goods_price>(SELECT ROUND(AVG(goods_price))FROM tdb_goods) ORDER BY goods_id DESC;
