Question

我有两个具有相同列的表。第一个表让我存储用户的账单，第二个表存储账单取消。

first table
-----------
id  - total
-----------
1   -   100
2   -    85
3   -    50

second table
-----------
id  - total
-----------
2   -    85


Result of JOIN
------------------------ 
id  - total    -  status
------------------------
1   -   100    -   OK
2   -    85    -   OK
3   -    50    -   OK
2   -    85    -   CANCEL

如何获得上述结果？

Answer 1

查询：

<强> SQLFIDDLEExample

SELECT t1.id,
       t1.total,
       'OK' AS status
FROM first t1
UNION ALL
SELECT t2.id,
       t2.total,
       'CANCEL' AS status
FROM second t2

结果：

| ID | TOTAL | STATUS |
-----|-------|--------|
|  1 |   100 |     OK |
|  2 |    85 |     OK |
|  3 |    50 |     OK |
|  2 |    85 | CANCEL |

Answer 2

您可以使用以下代码：

select *, 'OK' AS [Status] from [first table]
UNION ALL
select *, 'Cancel' from [second table]

Answer 3

使用UNION ALL集合运算符将两个表合并为一个。

SELECT id, total, 'OK' as status
FROM First_Table
UNION ALL
SELECT id, total, 'CANCEL' as status
FROM Second_Table

合并2个相同的表行

3 个答案: