MySQL的：重複的項目拉動

Question

當我拉MySQL的代碼如下：

SELECT distinct * 
FROM product_size AS ps 
INNER JOIN product_type AS pt ON ps.product_id = pt.product_id 
WHERE product_type = 'Business Card' 
; 

是拉動下面的圖片：

我所要做的是確保它當我們從我們的網站上拉出它時，只會在我們的網頁上拉出一個尺寸的實例。

所以基本上，當我們在我們的網站上做選擇時，我希望它拉大小。

當我把它在我們的網站，它涉及了以下內容：

http://screencast.com/t/eowXtDol6IOZ

Answer 1

我假設你的product_id是唯一的，這樣使用具有不同的product_id，而不是所有記錄。

SELECT distinct ps.product_id, ps.* 
FROM product_size AS ps 
INNER JOIN product_type AS pt ON ps.product_id = pt.product_id 
WHERE product_type = 'Business Card' ; 

Answer 2

您可以刪除不必要的物品容易這樣

SELECT DISTINCT size, produce_type, p_dimension 
FROM 
(SELECT distinct * 
FROM product_size AS ps 
INNER JOIN product_type AS pt ON ps.product_id = pt.product_id 
WHERE product_type = 'Business Card') 

或

SELECT DISTINCT rs.size, rs.produce_type, rs.p_dimension 
FROM 
(SELECT distinct * 
FROM product_size AS ps 
INNER JOIN product_type AS pt ON ps.product_id = pt.product_id 
WHERE product_type = 'Business Card') rs