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I have a table relevancies, where there are 2 colums. 1. User_id (It has two users, one and two) 2. Ratings

*Now I want to know the difference between ratings of two users(1,2). The rating difference should be two. *

Table: '+--------------------------+ | Tables_in_ndcg_reporting | +--------------------------+ | averages | | last_visited_queries | | products | | queries | | query_types | | ratings | | ratings_news | | relevancies | | schema_migrations | | sites | | users | +--------------------------+ Inside relevancies:

`+-----+--------+------------+----------+---------+---------------------+---------------------+

| id | rating | product_id | query_id | user_id | created_at |updated_at

| 726 | 5 | 1 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:43:07 |

| 727 | 5 | 2 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:43:21 |

| 728 | 5 | 3 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:43:31 |

| 729 | 5 | 4 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:43:32 |

| 730 | 4 | 5 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:43:53 |

| 731 | 5 | 6 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:43:55 |

| 732 | 4 | 7 | 1 | 2 | 2016-11-24 06:06:12 | 2016-12-28 10:25:52 |

| 733 | 4 | 8 | 1 | 2 | 2016-11-24 06:06:12 | 2016-12-27 12:44:24 |

| 734 | 5 | 9 | 1 | 2 | 2016-11-24 06:06:12 | 2016-11-24 12:44:01 |

| 735 | 4 | 10 | 1 | 2 | 2016-11-24 06:06:12 | 2016-12-28 10:25:53 | `

Shashank Sahu
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1 Answers1

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You might be looking for a self-join, like so:

select a.product_id
from relevencies a inner join relevencies b
on a.product_id = b.product_id and a.user_id <> b.user_id and a.rating >= (b.rating + 2);

If a user can give only a single review for a product, you can remove the a.user_id <> b.user_id condition.

Chitharanjan Das
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