sql有功能

Question

嗨我有以下的sql语句给我first_name和每个员工已经完成的所有工作总数，但现在我想要有first_name和job_id员工正在与另一个工作工人我有三个表共

下面是我用来获得名字和职位总数一共代码

SELECT first_name, COUNT(link.job_id) 
FROM employee, job, link 
WHERE job.job_id = link.job_id 
AND employee.employee_id = link.employee_id 
GROUP BY first_name 
HAVING (COUNT(link.job_id) > 1) ; 

有人可以帮助请

Answer 1

如何：

SELECT first_name, COUNT(link.job_id) 
FROM employee, job, link 
WHERE job.job_id = link.job_id 
AND employee.employee_id = link.employee_id 
AND job.job_id IN (SELECT job_id FROM link GROUP BY job_id HAVING COUNT(*) > 1) 
GROUP BY first_name 
HAVING (COUNT(link.job_id) > 1) ; 

子查询将获得涉及多个员工的所有工作。