在第一个表上分组，并保持第二个表的最大值

Question

Here are my tables

+----------+-----------+
|   id     |  user_id  |
+----------+-----------+
|    1     |     1     |
+----------+-----------+
|    2     |     1     |
+----------+-----------+
|    3     |     1     |
+----------+-----------+
|    4     |     2     |
+----------+-----------+
|    5     |     2     |
+----------+-----------+
|    6     |     2     |
+----------+-----------+
|    7     |     3     |
+----------+-----------+
|    8     |     3     |
+----------+-----------+
|    9     |     3     |
+----------+-----------+

My second table

+----------+---------+
|   id     |  score  |
+----------+---------+
|    1     |    10   |
+----------+---------+
|    2     |    20   |
+----------+---------+
|    3     |     5   |
+----------+---------+
|    4     |    40   |
+----------+---------+
|    5     |    15   |
+----------+---------+
|    6     |    10   |
+----------+---------+
|    7     |     5   |
+----------+---------+
|    8     |    30   |
+----------+---------+
|    9     |    10   |
+----------+---------+

I need to select the highest score achieved by a user from these tables.

Here is my MySql query

SELECT * FROM 
table_1 AS t1
INNER JOIN 
table_2 AS t2 ON 
t1.id = t2.id 
WHERE t2.score > 10
GROUP BY t1.user_id
ORDER BY t2.score DESC

My desire result is

+----------+-----------+---------+
|   id     |  user_id  |  score  |
+----------+-----------+---------+
|    4     |      2    |    40   |
+----------+-----------+---------+
|    8     |      3    |    30   |
+----------+-----------+---------+
|    2     |      1    |    20   |
+----------+-----------+---------+

But what I get is

+----------+-----------+---------+
|   id     |  user_id  |  score  |
+----------+-----------+---------+
|    4     |      2    |    40   |
+----------+-----------+---------+
|    1     |      1    |    10   |
+----------+-----------+---------+
|    7     |      3    |     5   |
+----------+-----------+---------+

MySql is always selecting the lowest id from table_1 when I'm using the GROUP BY clause

I tried using the MAX command like this

SELECT *, MAX(t2.score) AS max_score FROM 
table_1 AS t1
INNER JOIN 
table_2 AS t2 ON 
t1.id = t2.id 
WHERE t2.score > 10
GROUP BY t1.user_id
ORDER BY t2.score DESC
LIMIT 10

And the result I'm getting

+----------+-----------+---------+-----------+
|   id     |  user_id  |  score  | max_score |
+----------+-----------+---------+-----------+
|    4     |      2    |    40   |    40     |
+----------+-----------+---------+-----------+
|    1     |      1    |    10   |    20     |
+----------+-----------+---------+-----------+
|    7     |      3    |     5   |    30     |
+----------+-----------+---------+-----------+

I believe the result I wish it quite easy to get but I'm nowhere there.

Update 1

This question was marked duplicate but unfortunately I couldn't find any solution on that given page.

Here is the query that I'm trying but it fails.

SELECT * AS max_score FROM 
table_1 AS t1
INNER JOIN 
(
SELECT *, MAX(score) AS max_score
FROM table_2
GROUP BY t1.user_id
) AS t2
ON 
t1.id = t2.id 
WHERE t2.score > 10
ORDER BY t2.score DESC
LIMIT 10

It gives me the error Unknown column t1.user_id

I'm trying to get the highest value from the column score which is in table_2 and group the results by user_id which is in table_1 .

The examples given on those pages target only one table and I'cant make that work on my scenario.

Answer 1

Write a subquery that gets the max score for each user_id . Then join that with your tables to get the rows with that max score.

SELECT t1.id, t1.user_id, max_score
FROM table_1 AS t1
JOIN table_2 AS t2 ON t1.id = t2.id
JOIN (
    SELECT t1.user_id, MAX(t2.score) AS max_score
    FROM table_1 AS t1
    JOIN table_2 AS t2 on t1.id = t2.id
    GROUP BY t1.user_id) AS t_max
ON t1.user_id = t_max.user_id AND t2.score = t_max.max_score

DEMO