Question

以下选择语句为我提供了加班时间大于80的表：

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;

[！[输出] [1]] [1]

现在，我想将Empid与另一个表（t3）联接在一起，在这里必须将名字和姓氏连接起来，然后将其联接到上面的表中。

[！[此表] [2]] [2]

我似乎无法弄清楚如何将这两个select语句连接在一起并不断遇到错误

Answer 1

将您的查询用作子查询，并与表t3结合使用并使用concat函数

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

Answer 2

请尝试以下使用“与employees_2表联接”

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;

Answer 3

尝试一下：

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

给定一条选择语句，我该如何再选择更多？

3 个答案: