试试这个：

select empid, fullName, overtime
from (
    SELECT empid,
           overtime 
    FROM (
        SELECT empid, 
               IF(SUM(slength)>80,SUM(slength)-80,0) as overtime
        from schedule_2 group by empid
    ) as t where overtime > 0
) a join (
    select concat(firstName, ' ', lastName) fullName, 
           empid 
    from employees_2
) b on a.empid = b.empid

将您的查询用作子查询，并与表t3连接以供使用 concat 功能

select t1.empid,
concat(t3.firstname,t3.lastname) as name,
t1.overtime from    
(
select * from
(
SELECT empid, IF(SUM(slength)>80,SUM(slength)-80,0) 
as overtime from schedule_2 group by empid
) as t
where overtime >0
) as t1 join t3 on t1.empid=t3.empid

尝试使用下面的join with employees\ 2表

SELECT t.empid,overtime,concat(firstname,' ',lastname) as empname
FROM
(SELECT empid, IF(SUM(slength)>80,SUM(slength)-80,0) 
as 'overtime' from schedule_2 group by empid) as t
inner join employees_2 t1 on t.empid=t1.empid
where overtime >0;