【MYSQL】分數的排名
阿新 • • 發佈:2018-11-08
有以下資料
+----+-------+
| id | score |
+----+-------+
| 1 | 3.8 |
| 2 | 3.85 |
| 3 | 4.50 |
| 4 | 3.85 |
| 5 | 4.50 |
| 6 | 2.65 |
+----+-------+
把表格 tb_score的分數按從大到小排列,且把排名打印出來,相同的分數排名必須相同,結果如下
+-------+------+
| score | rank |
+-------+------+
| 4.50 | 1 |
| 4.50 | 1 |
| 3.85 | 2 |
| 3.85 | 2 |
| 3.8 | 3 |
| 2.65 | 4 |
+-------+------+
解答一:使用子查詢,在整個列表中找出有多少個大於或者等於此分數的不重複分數,倒序排列
SELECT score,
(select count(distinct score) from scores where score >=s.score)
Rank from scores s order by score DESC;
解答二,使用連表,當左表的分數小於等於右表的分數,對右表計數,按ID分組,按倒序排列
SELECT score,count(distinct s.score) as rank from scores a join scores s on a.score<=s.score group by a.id order by a.score desc