SAS SQL基于条件左联接，不删除表A中的行

我有两个表，希望根据特定的条件将表B左连接到A

联接基于'ID'（a.ID=b.ID），但是如果b.status\u date>=a.date，我只想从表b中引入两列'status\u date'和'flag\u y'

表A:

+------------+-----+--------+
|    date    | ID  | Flag_x |
+------------+-----+--------+
| 01/03/2019 | 100 | x      |
| 01/03/2019 | 101 | x      |
| 02/03/2019 | 102 | x      |
| 02/03/2019 | 103 | x      |
+------------+-----+--------+

+-------------+---------+--------+
| status_date | field_x | Flag_y |
+-------------+---------+--------+
| 15/03/2019  |     100 | y      |
| 10/01/2019  |     102 | y      |
+-------------+---------+--------+

+------------+-----+--------+-------------+--------+
|    date    | ID  | Flag_x | status_date | Flag_y |
+------------+-----+--------+-------------+--------+
| 01/03/2019 | 100 | x      | 15/03/2019  | y      |
| 01/03/2019 | 101 | x      |             |        |
| 02/03/2019 | 102 | x      |             |        |
| 02/03/2019 | 103 | x      |             |        |
+------------+-----+--------+-------------+--------+

表B:

+------------+-----+--------+
|    date    | ID  | Flag_x |
+------------+-----+--------+
| 01/03/2019 | 100 | x      |
| 01/03/2019 | 101 | x      |
| 02/03/2019 | 102 | x      |
| 02/03/2019 | 103 | x      |
+------------+-----+--------+

+-------------+---------+--------+
| status_date | field_x | Flag_y |
+-------------+---------+--------+
| 15/03/2019  |     100 | y      |
| 10/01/2019  |     102 | y      |
+-------------+---------+--------+

+------------+-----+--------+-------------+--------+
|    date    | ID  | Flag_x | status_date | Flag_y |
+------------+-----+--------+-------------+--------+
| 01/03/2019 | 100 | x      | 15/03/2019  | y      |
| 01/03/2019 | 101 | x      |             |        |
| 02/03/2019 | 102 | x      |             |        |
| 02/03/2019 | 103 | x      |             |        |
+------------+-----+--------+-------------+--------+

所需输出：

+------------+-----+--------+
|    date    | ID  | Flag_x |
+------------+-----+--------+
| 01/03/2019 | 100 | x      |
| 01/03/2019 | 101 | x      |
| 02/03/2019 | 102 | x      |
| 02/03/2019 | 103 | x      |
+------------+-----+--------+

+-------------+---------+--------+
| status_date | field_x | Flag_y |
+-------------+---------+--------+
| 15/03/2019  |     100 | y      |
| 10/01/2019  |     102 | y      |
+-------------+---------+--------+

+------------+-----+--------+-------------+--------+
|    date    | ID  | Flag_x | status_date | Flag_y |
+------------+-----+--------+-------------+--------+
| 01/03/2019 | 100 | x      | 15/03/2019  | y      |
| 01/03/2019 | 101 | x      |             |        |
| 02/03/2019 | 102 | x      |             |        |
| 02/03/2019 | 103 | x      |             |        |
+------------+-----+--------+-------------+--------+

我在下面尝试的代码删除了ID 102的行，在这种情况下，我想保留这一行，但不从表B中引入信息，因为“status\u date”在表A中的“date”之前。我假设需要在where子句中添加一些内容

PROC SQL;
Create Table Output As 
Select
a.*
,b.status_date
,b.flag_y

From Table_A as a
Left join Table_B as b
On b.ID = a.ID

Where b.status_date is Null or b.status_date >= a.date

;QUIT;

希望这是有意义的，有人可以帮助你，请尝试一下

SELECT 
  a.*
  ,b.status_date
  ,b.flag_y
FROM 
   Table_A as a
 LEFT JOIN Table_B as b
   ON b.ID = a.ID
   AND b.status_date >= a.date

请试试这个

SELECT 
  a.*
  ,b.status_date
  ,b.flag_y
FROM 
   Table_A as a
 LEFT JOIN Table_B as b
   ON b.ID = a.ID
   AND b.status_date >= a.date

---

您应该将日期筛选器添加到join子句中。您应该将日期筛选器添加到join子句中。因此，就这么简单！我有点困惑，因为在SAS Hadoop中尝试非常类似的东西时，它不喜欢日期条件。不管怎么说，这将是另一个要问的问题，因为事情就这么简单！我有点困惑，因为在SAS Hadoop中尝试非常类似的东西时，它不喜欢日期条件。无论如何，这将是另一个要问的问题