是的，这是可能的，通过做一个 FULL OUTER JOIN .
我也认为你想 JOIN 上 Objects 列：

SELECT
    COALESCE( t1.Objects, t2.Objects ) AS Objects,
    COALESCE( t1.Objects_Count, 0 ) AS Objects_Count,
--  t2.Status,
    CASE t2.status WHEN 1 THEN 'Online' ELSE 'Offline' END AS status
FROM
    (
        SELECT
            Objects,
            COUNT(*) AS Objects_count
        FROM
            table1
        GROUP BY
            Objects

    ) AS t1

    FULL OUTER JOIN
    (
        SELECT
            Objects, 
            status
        FROM
            table2

    ) AS t2 ON t1.Objects = t2.Objects

使用以下命令尝试 left join 上的表1和表2 Objects .

select 
    t1.Objects, 
    coalesce(COUNT (t1.*), 0) as  Objects_count,
    case 
        when t2.status = 1 then 'Online'
        else 'Offline'
    end as Status 
from table1 t1
left join table2 t2
on t1.Objects = t2.Objects
GROUP BY 
    Objects,  
    case 
        when t2.status = 1 then 'Online'
        else 'Offline'
    end

我将使用相关子查询：

SELECT t1.Objects, COUNT(*) AS Objects_count,
       (CASE WHEN EXISTS (SELECT 1
                          FROM table2 t2
                          WHERE t2.Objects = t1.Objects AND t2.status = 1
                         )
             THEN 'Online' ELSE 'Offline'
        END) as status
FROM table1 t1
GROUP BY t1.Objects

这将返回 table1 以及状态。
或者，如果 table2 没有重复行，可以使用简单的 LEFT JOIN 和聚合：

SELECT t1.Objects, COUNT(*) AS Objects_count,
       (CASE WHEN COUNT(t2.Objects) > 0 THEN 'Online' ELSE 'Offline' END) as status
FROM table1 t1 LEFT JOIN
     table2 t2
     ON t2.Objects = t1.Objects AND t2.status = 1
GROUP BY t1.Objects;