Html 从喜欢mysql中特定产品的人那里找到最喜欢的产品

Html 从喜欢mysql中特定产品的人那里找到最喜欢的产品,html,mysql,sql,database,Html,Mysql,Sql,Database,我想知道如何通过下表模式从喜欢H135产品的用户那里找到最喜欢的产品: CREATE TABLE likes (`user_id` int,`product_id`int) ; INSERT INTO likes (`user_id`,`product_id`) VALUES (1,22), (1,44), (2,33), (2,44), (3,22), (3,55), (4,44), (4,11), (5

我想知道如何通过下表模式从喜欢H135产品的用户那里找到最喜欢的产品:

CREATE TABLE likes
    (`user_id` int,`product_id`int)
;

INSERT INTO likes
    (`user_id`,`product_id`)
VALUES
    (1,22),
    (1,44),
    (2,33),
    (2,44),
    (3,22),
    (3,55),
    (4,44),
    (4,11),
    (5,22),
    (5,44),
    (5,33) 

;
CREATE TABLE products
    (`product_id` int,`product_name`varchar(30))
;

INSERT INTO products
    (`product_id`,`product_name`)
VALUES
    (11,'N570'),
    (22,'KA89'),
    (33,'A321'),
    (44,'H135'),
    (55,'C839')
;
预期的输出应该是这样的

Liked_product  users_who_like_it_also_like     Result   
H135           KA89                            3
我尝试过自联接,但没有产生任何结果:

SELECT p.product_name,p2.product_name AS other_liked_products,
COUNT(l2.product_id) AS users_who_like_it_also_like 
FROM likes l 
INNER JOIN products p ON p.product_id = l.product_id
INNER JOIN likes l2 ON l.product_id = l2.product_id
INNER JOIN products p2 ON p2.product_id = l2.product_id
WHERE l.product_id = 44 
AND l2.product_id <> 44
GROUP BY l.product_id
LIMIT 1

如果您不在乎领带,您可以使用:

select 'H135' as liked_product,
       p.product_name as users_who_like_it_also_like,
       count(*) as result
  from likes l
  join products p
    on p.product_id = l.product_id
 where exists (select 1
          from likes x
         where x.user_id = l.user_id
           and x.product_id = 44)
   and l.product_id <> 44
 group by p.product_name
 order by 3 desc
 limit 1
小提琴:

在您的示例数据中,KA89的实际计数为2,并且与A321绑定

这将在一行上的聚合列表中显示两者,并与计数2绑定:

select liked_product,
       group_concat(users_who_like_it_also_like) as users_who_like_it_also_like,
       result
  from (select 'H135' as liked_product,
               p.product_name as users_who_like_it_also_like,
               count(*) as result
          from likes l
          join products p
            on p.product_id = l.product_id
         where exists (select 1
                  from likes x
                 where x.user_id = l.user_id
                   and x.product_id = 44)
           and l.product_id <> 44
         group by p.product_name) x
 group by liked_product, result
 order by result desc limit 1
Fiddle:

您可能只需要在group by之后使用order by语句。