sql有功能

Question

嗨我有以下的sql語句給我first_name和每個員工已經完成的所有工作總數，但現在我想要有first_name和job_id員工正在與另一個工作工人我有三個表共

下面是我用來獲得名字和職位總數一共代碼

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) ; 

有人可以幫助請

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) ; 

子查詢將獲得涉及多個員工的所有工作。