MySQL max 和 count 聚合函数

Question

所以我有三张桌子

CREATE TABLE Personnel(
    IdPersonnel INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
    Name        VARCHAR(45) NOT NULL,
    Surename    VARCHAR(45) NOT NULL,
    Department  VARCHAR(45) NOT NULL,
    Salary      INT NOT NULL,
    Birthday    DATE NOT NULL
);

CREATE TABLE Doctor(
    IdDoctor     INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
    fk_Personnel INT NOT NULL
);

CREATE TABLE Visit(
    IdVisit     INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
    Date        DATE NOT NULL,
    ControlDate DATE,
    fk_Patient  INT NOT NULL,
    fk_Doctor   INT NOT NULL,
);

从这三个表中，我需要找到一位访问次数最多的医生。

SELECT p.Name, p.Surname, COUNT(*) visits
  FROM Visit v
  JOIN Doctor d
    ON v.fk_Doctor = d.IdDoctor
  JOIN Personnel p
    ON d.fk_Personnel = p.IdPersonnel
 GROUP BY d.IdDoctor
 ORDER BY COUNT(*) DESC 
 LIMIT 1;

我使用了这个查询，结果是正确的，但我必须使用 MAX() function。我正在使用 MySQL 社区服务器 8.0.26

Answer 1

select P.Name, P.Surename, P.IdPersonnel ,count(*) from Visit V
inner join Doctor D on V.fk_Doctor = D.IdDoctor
inner join Personnel P on D.fk_Personnel = P.IdPersonnel
group by P.Name, P.Surename, P.IdPersonnel
having count(*) = (
select max(visits) from
(select fk_Doctor, count(*) visits from Visit group by fk_Doctor) a
)