README.md

574. 当选者

English Version

题目描述

表: Candidate

+-----+---------+
| id  | Name    |
+-----+---------+
| 1   | A       |
| 2   | B       |
| 3   | C       |
| 4   | D       |
| 5   | E       |
+-----+---------+  

表: Vote

+-----+--------------+
| id  | CandidateId  |
+-----+--------------+
| 1   |     2        |
| 2   |     4        |
| 3   |     3        |
| 4   |     2        |
| 5   |     5        |
+-----+--------------+
id 是自动递增的主键，
CandidateId 是 Candidate 表中的 id.

请编写 sql 语句来找到当选者的名字，上面的例子将返回当选者 B.

+------+
| Name |
+------+
| B    |
+------+

注意:

1. 你可以假设没有平局，换言之，最多只有一位当选者。

 

解法

SQL

# Write your MySQL query statement below
SELECT
    Name
FROM
    (
        SELECT
            CandidateId AS id
        FROM
            Vote
        GROUP BY
            CandidateId
        ORDER BY
            COUNT(id) DESC
        LIMIT 1
    ) AS t
INNER JOIN
    Candidate c
ON
    t.id = c.id;