README_EN.md

574. Winning Candidate

中文文档

Description

Table: Candidate

+-------------+----------+
| Column Name | Type     |
+-------------+----------+
| id          | int      |
| name        | varchar  |
+-------------+----------+
id is the primary key column for this table.
Each row of this table contains information about the id and the name of a candidate.

 

Table: Vote

+-------------+------+
| Column Name | Type |
+-------------+------+
| id          | int  |
| candidateId | int  |
+-------------+------+
id is an auto-increment primary key.
candidateId is a foreign key to id from the Candidate table.
Each row of this table determines the candidate who got the ith vote in the elections.

 

Write an SQL query to report the name of the winning candidate (i.e., the candidate who got the largest number of votes).

The test cases are generated so that exactly one candidate wins the elections.

The query result format is in the following example.

 

Example 1:

Input: 
Candidate table:
+----+------+
| id | name |
+----+------+
| 1  | A    |
| 2  | B    |
| 3  | C    |
| 4  | D    |
| 5  | E    |
+----+------+
Vote table:
+----+-------------+
| id | candidateId |
+----+-------------+
| 1  | 2           |
| 2  | 4           |
| 3  | 3           |
| 4  | 2           |
| 5  | 5           |
+----+-------------+
Output: 
+------+
| name |
+------+
| B    |
+------+
Explanation: 
Candidate B has 2 votes. Candidates C, D, and E have 1 vote each.
The winner is candidate B.

Solutions

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;