INSERT tdb_goods_cates (cate_name) SELECT goods_cate FROM tdb_goods GROUP BY goods_cate;
INSERT tdb_goods_cates (cate_name) SELECT DISTINCT goods_cate FROM tdb_goods;
INSERT tdb_goods_cates (cate_name) SELECT DISTINCT goods_cate FROM tdb_goods;
2020-06-14
你們這樣寫試試
SELECT p.type_id,p.type_name,count(s.type_name) num FROM tdb_goods_types AS p LEFT JOIN tdb_goods_types AS s ON s.parent_id = p.type_id GROUP BY p.type_id ORDER BY p.type_id;
SELECT p.type_id,p.type_name,count(s.type_name) num FROM tdb_goods_types AS p LEFT JOIN tdb_goods_types AS s ON s.parent_id = p.type_id GROUP BY p.type_id ORDER BY p.type_id;
2020-05-21
數據插入:
若省略列名,需為每個列賦值
若沒有為記錄的某個字段賦值,則顯示NULL
若不給自增字段賦值,或為其賦值為NULL,或為其賦值為DEFAULT,都不改變其規則
若列有定義默認約束。當插入記錄時,如果沒有為字段賦值或為其賦值為DEFAULT,則自動賦予默認值
若省略列名,需為每個列賦值
若沒有為記錄的某個字段賦值,則顯示NULL
若不給自增字段賦值,或為其賦值為NULL,或為其賦值為DEFAULT,都不改變其規則
若列有定義默認約束。當插入記錄時,如果沒有為字段賦值或為其賦值為DEFAULT,則自動賦予默認值
2020-05-19