mysql - 加入两个表并按 xyz 分组

Question

我有两张桌子

表格1：

    ref       status

    abc     1
    abc     1
    abc     2
    abc     3
    abc     5(not in Table2)
    abc     5(not in Table2)

表 2：

    ref          status

    abc     1
    abc     1
    abc     2
    abc     3
    abc             4(not in Table1)
    abc     4(not in Table1)

我想加入这两个表并执行分组，以便最终结果如下所示：

结果表：参考状态

    abc     1
    abc     2
    abc     3
    abc     4
    abc     5

我试过这个

    SELECT DISTINCT Table1.ref, Table1.status, Table2.ref, Table2.status
    FROM Table1, Table2
    GROUP BY Table1.ref, Table1.status, Table2.ref, Table2.status;

Answer 1

SELECT DISTINCT ref, status
FROM
(
    SELECT ref, status
    FROM Table1
    UNION ALL
    SELECT ref, status
    FROM Table2
) x

SQL 小提琴示例

Answer 2

试试下面的代码：

SELECT DISTINCT ref, status
FROM Table1
UNION 
SELECT DISTINCT ref, status
FROM Table2