限制SQL查询中每个ID的行数 [英] Limit number of rows per id in a SQL query

问题描述

我想限制每个brand_id的10个产品的结果.这是我的查询的样子:

I want to limit the results of 10 products for each brand_id. Here's how my query looks like:

SELECT 
products.id, products.brand_id
FROM products
  JOIN (
    select id, brand_id
    from products limit 10) 
    pinner ON products.id = pinner.id
WHERE pinner.brand_id IN ('1', '2','3') ;

那显然是行不通的.有什么建议吗?

That obviously does not work. Any suggestions?

这篇文章为我提供了解决方案:

This post helped me with the solution: http://www.xaprb.com/blog/2006/12/07/how-to-select-the-firstleastmax-row-per-group-in-sql/

推荐答案

从另一个答案开始适应

  set @brand_id= '';
  set @num = 0;

  select
  products.id, products.brand_id,
  @num := if(@brand_id= brand_id, @num + 1, 1) as dummy_1,
  @brand_id:= brand_id as dummy_2,
  @num as row_number
  from products
  where brand_id IN ('1', '2','3')
  group by
  brand_id,
  row_number
  having row_number <= 10;

这篇关于限制SQL查询中每个ID的行数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！