SQL查询选择每个id的一个图像

Question

我需要选择每个产品的第一个拇指图像（这里是它的实体ID）

我的查询

SELECT entity_id as product_id, value FROM catalog_product_entity_media_gallery

但是它返回我需要查询的所有图像从每个id中选择第一张图像可以提供任何帮助。

db table

Answer 1

您可以将从0索引限制的返回行限制为1个记录。

SELECT entity_id as product_id,value FROM catalog_product_entity_media_gallery GROUP BY entity_id

Answer 2

SELECT entity_id as product_id, value FROM catalog_product_entity_media_gallery GROUP BY entity_id

Answer 3

试试这个，使用GROUP BY进行分组并命令它们获取第一个

SELECT entity_id as product_id, value FROM catalog_product_entity_media_gallery GROUP BY entity_id ORDER BY entity_id

Answer 4

你使用GROUP BY条款

SELECT entity_id as product_id, value FROM catalog_product_entity_media_gallery 
GROUP BY entity_id ORDER BY entity_id

  

ORDER BY entity_id获取第一个拇指图像

Answer 5

这是查询

SELECT entity_id as product_id, value FROM catalog_product_entity_media_gallery GROUP BY product_id ORDER BY `value_id` ASC

  

当您执行 GROUP BY 时，您正在对所有相似内容进行分组   product_id或entity_id为one＆amp;因为你 ORDER BY value_id by   升序第一个插入的行将位于顶部并按

分组

检查这两个链接以获取更多详细信息http://www.w3schools.com/sql/sql_groupby.asp＆amp; http://www.w3schools.com/sql/sql_orderby.asp