MySQL 查询 : How can I find top 5 images in each brand ?

Question

mysql表中的数据如下。

brand_id|image_id|downloads
--------|--------|---------
8       |9       |8    
35      |2829    |4    
28      |2960    |3    
28      |2961    |3    
28      |3041    |3    
35      |2831    |3    
28      |2965    |3    
35      |2832    |3    
28      |2959    |2    
28      |2976    |2    
35      |2894    |2  

如何在每个品牌中找到具有 GROUP_CONCAT 功能的前 5 个图像？我希望得到以下返回:

brand_id|image_ids                
--------|--------------------------
8       |9                       
35      |2829,2831,2832,2894     
28      |2960,2961,3041,2965,2959

Answer 1

使用SUBSTRING_INDEX

SELECT
  brand_id,
  SUBSTRING_INDEX(GROUP_CONCAT(image_id SEPARATOR ','),',',5) AS image_ids
FROM Table1
GROUP BY brand_id

fiddle