如何僅從多個已連接的表中返回單個圖像行？

我有一些收集產品信息的sql。它還從連接的表中檢索圖像。有時產品會有多個圖像（有時不會），這會導致結果中出現重複。如何更改此查詢以僅從連接的圖像表中返回單個圖像（或無圖像） - image_d，image_p，image_t？如何僅從多個已連接的表中返回單個圖像行？

SELECT 
    products_categories.categoryid, 
    products.productid, 
    products.product, 
    products.descr, 
    products.rating, 
    products.title_tag, 
    images_d.image_path AS imaged, 
    images_p.image_path AS imagep, 
    images_t.image_path AS imaget, 
    clean_urls.clean_url 
FROM products_categories 
INNER JOIN products ON products_categories.productid = products.productid 
LEFT JOIN images_d ON products.productid = images_d.id 
LEFT JOIN images_p ON products.productid = images_p.id 
LEFT JOIN images_t ON products.productid = images_t.id 
LEFT JOIN clean_urls ON products.productid = clean_urls.resource_id 
WHERE products_categories.categoryid = 265 
AND products_categories.main = 'Y' 
AND products.forsale = 'Y' 
ORDER BY productid

謝謝。

來源

2012-02-23 stack asker

我假設給定的image_x表中有多個圖像。您可以使用group_concat()多個值硬塞到一個CSV列：

SELECT 
    products_categories.categoryid, 
    products.productid, 
    products.product, 
    products.descr, 
    products.rating, 
    products.title_tag, 
    group_concat(images_d.image_path) AS imaged, 
    group_concat(images_p.image_path) AS imagep, 
    group_concat(images_t.image_path) AS imaget, 
    clean_urls.clean_url 
FROM products_categories 
INNER JOIN products ON products_categories.productid = products.productid 
LEFT JOIN images_d ON products.productid = images_d.id 
LEFT JOIN images_p ON products.productid = images_p.id 
LEFT JOIN images_t ON products.productid = images_t.id 
LEFT JOIN clean_urls ON products.productid = clean_urls.resource_id 
WHERE products_categories.categoryid = 265 
AND products_categories.main = 'Y' 
AND products.forsale = 'Y' 
GROUP BY 1,2,3,4,5,6,10 
ORDER BY productid

來源

2012-02-23 04:51:56 Bohemian

似乎並沒有得以順利，我還是得到重複的productid的返回。 – 2012-02-23 05:10:26

@stackasker：難道是因爲重複產品屬於多個類別？ – 2012-02-23 07:40:05

@AndriyM：不，那不是。當我將提議的查詢更改爲2組時，它似乎會返回正確的結果。更多的睡眠，更多的測試。 – 2012-02-23 10:00:56

如何僅從多個已連接的表中返回單個圖像行？

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