我尝试编写一个查询，以便在virtmart 2中检索我们产品的完整信息。
首先，我尝试使用单个INNER JOIN，如下面的示例：
$query ="select p.`virtuemart_product_id`, p.`product_name`, p.`product_s_desc`, `pmqbw_virtuemart_product_categories`.`virtuemart_category_id`
FROM `pmqbw_virtuemart_products_el_gr` AS p
INNER JOIN `pmqbw_virtuemart_product_categories` ON p.`virtuemart_product_id`=`pmqbw_virtuemart_product_categories`.`virtuemart_product_id`
LIMIT 0 ,10";
以上效果很好！
然后我试着变得更复杂，我写了以下内容：
$query ="select p.`virtuemart_product_id`, p.`product_name`, p.`product_s_desc`, `pmqbw_virtuemart_product_categories`.`virtuemart_category_id`, `pmqbw_virtuemart_categories_el_gr`.`category_name`
FROM `pmqbw_virtuemart_products_el_gr` AS p
INNER JOIN p
ON `pmqbw_virtuemart_product_categories`.`virtuemart_product_id`=p.`virtuemart_product_id`
INNER JOIN `pmqbw_virtuemart_categories_el_gr` AS x
ON x.`virtuemart_category_id`=`pmqbw_virtuemart_product_categories`.`virtuemart_category_id`
LIMIT 0 ,10";
但这里出了点问题，我无法理解。
之后我将尝试检索更多表和更多联接，以便提供我需要的产品数据。
提前感谢您的帮助！
实际上我想从下表中检索数据。
来自pmqbw_virtuemart_products_el_gr I want fields: product_name, product_s_desc, virtuemart_product_id`
来自pmqbw_virtuemart_product_categories我想要字段：virtuemart_product_id，virtuemart_category_id
来自pmqbw_virtuemart_categories_el_gr我想要字段：virtuemart_category_id，category_name
来自pmqbw_virtuemart_product_medias我想要字段：virtuemart_product_id，virtuemart_media_id
pmqbw_virtuemart_medias我想要字段：virtuemart_media_id，file_url，file_url_thumb其中file_mimetype = image / jpeg AND file_type = product
我尝试使用左连接进行不同的查询，但不能正常工作。
$sql = "SELECT N.product_name,I.virtuemart_media_id,M.virtuemart_product_id,MN.category_name
FROM pmqbw_virtuemart_categories_el_gr AS M
LEFT JOIN pmqbw_virtuemart_products AS P ON P.virtuemart_product_id = M.virtuemart_product_id
LEFT JOIN pmqbw_virtuemart_products_el_gr AS N ON N.virtuemart_product_id = M.virtuemart_product_id
LEFT JOIN pmqbw_virtuemart_product_medias AS I ON I.virtuemart_product_id = M.virtuemart_product_id
LEFT JOIN pmqbw_virtuemart_product_categories AS MN ON MN.virtuemart_category_id = M.virtuemart_category_id
WHERE M.virtuemart_category_id = 1";
任何帮助将不胜感激！
谢谢！
谢谢大家的帮助！
运行正常的查询如下：
$sql = "SELECT DISTINCT X.virtuemart_product_id, X.product_name, M.category_name, Y.virtuemart_product_id, W.file_url
FROM pmqbw_virtuemart_products_el_gr AS X
INNER JOIN pmqbw_virtuemart_product_categories AS P ON P.virtuemart_product_id = X.virtuemart_product_id
AND P.virtuemart_category_id =2
INNER JOIN pmqbw_virtuemart_categories_el_gr AS M ON M.virtuemart_category_id = P.virtuemart_category_id"
INNER JOIN pmqbw_virtuemart_product_medias AS Y ON Y.virtuemart_product_id = X.virtuemart_product_id
INNER JOIN pmqbw_virtuemart_medias AS W ON W.virtuemart_media_id = Y.virtuemart_media_id;
萌芽的是，每个产品都有两个或更多的图像，我只想要一个。 我必须考虑一些事情才能消除它！ 如果有人在他的脑海中寻求帮助，那将非常受欢迎！
谢谢！
好的，我找到了GROUP BY Y.virtuemart_product_id的解决方案 ：）
谢谢大家！