mysql - 左连接导致重复行

Question

我有一个查询可以成功地从我的产品表中获取独特的产品并显示它们。我正在尝试将图标表添加到组合中，其中某些产品可以有多个图标。问题是我试图只使用连接，例如当一个产品有 2 个图标时，我将为该 1 个产品选择 2 行。

这是我的 sql:

    SELECT p.products_image, 
           pd.products_name, 
           p.products_id, 
           p.products_model, 
           p.manufacturers_id, 
           p.products_price, 
           p2i.icons_id, 
           p.products_tax_class_id, 
           IF(s.status, s.specials_new_products_price, NULL)             AS 
           specials_new_products_price, 
           IF(s.status, s.specials_new_products_price, p.products_price) AS 
           final_price 
    FROM   products p 
           LEFT JOIN manufacturers m 
                  ON p.manufacturers_id = m.manufacturers_id 
           LEFT JOIN specials s 
                  ON p.products_id = s.products_id 
           LEFT JOIN products_to_categories p2c 
                  ON p.products_id = p2c.products_id 
           LEFT JOIN products_description pd 
                  ON p.products_id = pd.products_id 
           LEFT JOIN products_to_icon p2i 
                  ON p.products_id = p2i.products_id 
    WHERE  p.products_status = '1' 
           AND pd.language_id = '1' 
           AND p2c.categories_id = '36'

Answer 1

在末尾添加一个 GROUP BY 子句。如果你仍然想要所有的图标 id，你可以结合 group_concat

例如:

SELECT p.products_image, 
       pd.products_name, 
       p.products_id, 
       group_concat(p2i.icons_id separator ",") as icons_ids
       (...)
WHERE  p.products_status = '1' 
       AND pd.language_id = '1' 
       AND p2c.categories_id = '36'
GROUP BY p.products_id