Show top N scores in MySQL 8 without duplicates by category

问题

I have the following table in MySQL 8.0.15:

CREATE TABLE golf_scores (person TEXT, score INT);
INSERT INTO golf_scores VALUES ('Angela', 40),('Angela', 45),('Angela', 55),('Peter',45),('Peter',55),('Rachel', 65),('Rachel',75),('Jeff',75);

SELECT * FROM golf_scores;
+--------+-------+
| person | score |
+--------+-------+
| Angela |    40 |
| Angela |    45 |
| Angela |    55 |
| Peter  |    45 |
| Peter  |    55 |
| Rachel |    65 |
| Rachel |    75 |
| Jeff   |    75 |
+--------+-------+

I am trying to get the following top 3 scores:

SELECT * FROM golf_scores;
+--------+-------+
| person | score |
+--------+-------+
| Angela |    40 |
| Peter  |    45 |
| Rachel |    65 |
+--------+-------+

In other words, I want the best (lowest) 3 golf score without having duplicates by person. I'm not worried about ties; I'd still just like three results.

I thought this query would do it:

SELECT person, MIN(score) FROM golf_scores GROUP BY person ORDER BY score LIMIT 3;

but I get the following error:

ERROR 1055 (42000): Expression #1 of ORDER BY clause is not in GROUP BY clause and contains nonaggregated column 'records.golf_scores.score' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

Adding score to the GROUP BY list just returns the lowest 3 scores total, regardless of duplicates in the person column.

How can I get the desired output in MySQL?

回答1:

since order by clause is executed after select clause,try putting an aliases for min(score) .

SELECT person, MIN(score) as min_score FROM golf_scores GROUP BY person ORDER BY min_score LIMIT 3;

回答2:

You can try using row_number()

    select * from
    (
         SELECT person, score,row_number() over(partition by person order by score) as rn
         FROM golf_scores 
    )A where rn=1
    ORDER BY score LIMIT 3

来源：https://stackoverflow.com/questions/54702226/show-top-n-scores-in-mysql-8-without-duplicates-by-category

标签

mysql

group-by

mysql-8.0