Mysql 一对多关系的SQL查询

这是我的数据库：

员工表：

employee\u id int（10）不为空，

firstname varchar（50）不为空，

lastname varchar（50）不为空，

用户名varchar（15）不为空，

password varchar（25）非空默认“password”，

联系人号码varchar（13）不为空，

电子邮件地址varchar（50）不为空，

位置varchar（50）不为空，

teamleader\u id int（11）默认为空

服务表：

服务\u id int（10）不为空，


ticket\u id int（10）不为空，


employee\u id int（10）不为空，


状态varchar（15）不为空，


开始时间日期时间不为空，


time\u在datetime中默认为空，


time\u out datetime默认为空，


service\u notes varchar（500）默认值为NULL


查询：

SELECT * FROM employee AS e 
LEFT JOIN service AS s ON e.employee_id = s.employee_id
WHERE (s.status IS NULL OR s.status = 'Completed') 
AND e.teamleader_id = ?

编辑：

我想选择除service.status='Continuous'之外的所有员工，假设您只需要已完成服务的员工列表（不包括未完成服务的员工，并且每个员工只显示一项服务）

SELECT employee.*, COUNT(service.status)
FROM employee LEFT JOIN service ON service.employee_id = employee.employee_id
WHERE employee.employee_id NOT IN ( SELECT DISTINCT service.employee_id FROM service WHERE service.status = 'Ongoing')
AND teamleader_id = 1
GROUP BY employee.employee_id;

或者如果您确实想列出尚未完成任何服务的员工

SELECT employee.*, COUNT(service.status)
FROM employee LEFT JOIN service ON service.employee_id = employee.employee_id
WHERE ( service.status IS NULL OR service.status = 'Completed' )
AND teamleader_id = 1
GROUP BY employee.employee_id;

或者，如果您想要除service.status=‘持续’之外的所有

SELECT employee.*, COUNT(service.status)
FROM employee LEFT JOIN service ON service.employee_id = employee.employee_id
WHERE employee.employee_id NOT IN ( SELECT DISTINCT service.employee_id FROM service WHERE service.status = 'Ongoing')
AND teamleader_id = 1
GROUP BY employee.employee_id;

测试

您只需将DISTINCT添加到查询中：

SELECT DISTINCT e.* FROM employee e LEFT JOIN service s ON e.employee_id = s.employee_id
WHERE(s.status is null OR s.status = 'Completed') and teamleader_id = 3

它会过滤重复的员工
如果我想选择除服务状态为“正在进行”的员工之外的所有员工，该怎么办
SELECT DISTINCT e.* FROM employee e LEFT JOIN service s ON e.employee_id = s.employee_id
WHERE(s.status is null OR s.status = 'Completed') and teamleader_id = 3