如何将两张表合二为一？

Question

我有两张表 (A) 和 (B)，在不同的日期包含几乎相同的信息。

表（A）

+----+------------+----------+-------+
|ID  | Date       | Status   | Amount|
+----+------------+----------+-------+
| A1 | 01/14/2011 | Received |15     |
| A2 | 01/18/2011 | Received |65     |
| T3 | 01/9/2011  | Received |85     |
| X7 | 02/16/2011 | Received |35     |
| A5 | 01/3/2011  | Received |10     |
+----+------------+----------+-------+

表（B）

+----+------------+----------+-------+
|ID  | Date       | Status   | Amount|
+----+------------+----------+-------+
| A1 | 03/31/2012 | Approved |15     |
| A2 | 03/31/2012 | Denied   |65     |
| A3 | 03/31/2012 | Approved |85     |
| A7 | 03/31/2012 | Received |35     |
| A5 | 03/31/2012 | pending  |10     |
+----+------------+----------+-------+

我正在尝试合并它们以获得这样的新表（结果）：

表格（结果）

+----+------------+----------+-------+
|ID  | Date       | Status   | Amount|
+----+------------+----------+-------+
| A1 | 01/14/2011 | Received |15     |
| A1 | 03/31/2012 | Approved |15     |
| A2 | 01/18/2011 | Received |65     |
| A2 | 03/31/2012 | Denied   |65     |
| A5 | 01/3/2011  | Received |10     |
| A5 | 03/31/2012 | pending  |10     |
+----+------------+----------+-------+

我使用了这个代码：

SELECT *
FROM table1
JOIN table2
ON table1.id = table2.id
ORDER BY table1.id;

结果如下：

+----+------------+----------+-------+------------+------------+---------+
| ID | Date       | Status   | Amount| Date_1     | Status_1   | Amount_1|
+----+------------+----------+-------+------------+------------+---------+
| A1 | 01/14/2011 | Received |15     |03/31/2012  | Approved   |15       |
+----+------------+----------+-------+------------+------------+---------+

它工作正常，但不是我想要的。我不想并排重复列。我在考虑使用 INSERT INTO 或 UNION ALL，但我不确定。

Answer 1

使用 UNION 时，每个表中仅包含另一表中对应行的行：

SELECT * FROM TableA a
WHERE EXISTS (
  SELECT 1 FROM TableB
  WHERE ID = a.ID AND Amount = a.Amount AND Status <> a.Status
)
UNION
SELECT * FROM TableB b
WHERE EXISTS (
  SELECT 1 FROM TableA
  WHERE ID = b.ID AND Amount = b.Amount AND Status <> b.Status
)
ORDER BY ID;

我不确定Amount = x.Amount 的情况。也许你想删除它。

Answer 2

这是一个简单的联合所有查询来完成这项工作：

select * from a where id in (select id from b)
union all
select * from b where id in (select id from a)
order by id, date;

Answer 3

试试这个：

SELECT t2.*
FROM table1 t1
INNER JOIN 
(
    --Get results from both tables
    SELECT *
    FROM table1
    UNION ALL
    SELECT *
    FROM table2
) t2
    on t1.ID = t2.ID
ORDER BY t2.ID;

Answer 4

select x.id, x.status, x.amount, y.status, y.amount
from 
(
select 'A1' id, 'received' status, 15 amount from dual
union all
select 'A2' id, 'received' status, 65 amount from dual
) x,
 (
select 'A1' id, 'approved' status, 15 amount from dual
union all
select 'A2' id, 'denied' status, 65 amount from dual
) y
where x.id = y.id

希望对你有帮助！

Answer 5

如果目标（您还没有真正描述过）是报告两个表中都存在 ID 的表中的行，那么您可能想要这样：

select id, somedate, status, amount
from   ( select id, somedate, status, amount from table_a
         union all
         select id, somedate, status, amount from table_b )
where  id in
       ( select id from table_a
         intersect
         select id from table_b )

Answer 6

使用 UNION：

SELECT ID, Date, Status, Amount
FROM table1
UNION
SELECT ID, Date, Status, Amount
from table2
ORDER BY ID;