如何使用數據庫中的另一個表來更新表記錄？

Question

表之一：products其中有像

products_id 
products_price 
master_categories_id 

表兩個字段：specials。此表是空的，菲爾茲在它是

specials_id (an autoincrement field) 
products_id (the value same as table one) 
specials_new_products_price (the value equals products_price-(products_price*0.05)) 
specials_date_added (the value like this 2011-12-05 12:17:44) 
specials_last_modified (the value like this 2011-12-05 12:19:10) 
expires_date (2011-12-31) 
date_status_change (the value like this 2011-12-05 12:19:10) 
status (1) 
specials_date_available (2011-11-29) 

現在，我要插入的數據

("SELECT products_id,products_price FROM products where master_categories_id=79") 
into table 2. and set the `status=1, specials_date_available=2011-11-29, 
expires_date=2011-12-31`.`products_id(the value same as table one) 

specials_new_products_price (the value equals products_price-(products_price*0.05)) 

其餘字段的值是由你。

我覺得哪個不好，寫一個php文件做插入。選擇products_id，products_price，然後把它們放在一個接一個的txt文件中，然後把文件內容放到表格2中，但是我不知道如何將文本文件數據放到table2中，以及如何設置剩餘字段值？

Answer 1

insert into specials 
(products_id, products_price,status,specials_date_available,expires_date) 
SELECT products_id,products_price*0.95 as products_price, 
1, '2011-11-29', '2011-12-31' 
FROM products where master_categories_id=79 

或類似的東西。