Question

我的选择查询：

SELECT CUSTID, EVENT_DTM, CURRENT_LOC, FROM_LOC FROM TABLE

返回以下结果：

+--------+----------------------------+-------------+----------+
| CUSTID | EVENT_DTM                  | CURRENT_LOC | FROM_LOC |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 01:33:00.000000 | FRONTDOOR   |          |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 03:50:00.000000 | FRONTDOOR   |          |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 04:32:00.000000 | FOYER       |          |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 05:42:00.000000 | TEMP-ONE    | FOYER    |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 05:58:00.000000 | KITCHEN     | TEMP-ONE |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 10:43:00.000000 | POOL        | KITCHEN  |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 13:01:00.000000 | BEDROOM     | POOL     |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-18 14:00:00.000000 | BEDROOM     |          |
+--------+----------------------------+-------------+----------+

我想编写一条select语句，以便当CURRENT_LOC = TEMP-ONE并且有一个对应的FROM_LOC = TEMP-ONE时，将合并行，并且查询结果将是：

+--------+----------------------------+-------------+----------+
| CUSTID | EVENT_DTM                  | CURRENT_LOC | FROM_LOC |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 01:33:00.000000 | FRONTDOOR   |          |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 03:50:00.000000 | FRONTDOOR   |          |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 04:32:00.000000 | FOYER       |          |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 05:58:00.000000 | KITCHEN     | FOYER    |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 10:43:00.000000 | POOL        | KITCHEN  |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-17 13:01:00.000000 | BEDROOM     | POOL     |
+--------+----------------------------+-------------+----------+
| 1      | 2000-02-18 14:00:00.000000 | BEDROOM     |          |
+--------+----------------------------+-------------+----------+

是否存在SQL解决此问题的方法？

谢谢，马特

Answer 1

以下查询返回您提供的结果。

WITH MYTAB (CUSTID, EVENT_DTM, CURRENT_LOC, FROM_LOC) AS 
(
VALUES
  (1, '2000-02-17 01:33:00.000000', 'FRONTDOOR', '')
, (1, '2000-02-17 03:50:00.000000', 'FRONTDOOR', '')
, (1, '2000-02-17 04:32:00.000000', 'FOYER', '')
, (1, '2000-02-17 05:42:00.000000', 'TEMP-ONE', 'FOYER    ')
, (1, '2000-02-17 05:58:00.000000', 'KITCHEN', 'TEMP-ONE ')
, (1, '2000-02-17 10:43:00.000000', 'POOL', 'KITCHEN  ')
, (1, '2000-02-17 13:01:00.000000', 'BEDROOM', 'POOL     ')
, (1, '2000-02-18 14:00:00.000000', 'BEDROOM', '')
)
SELECT A.CUSTID, A.EVENT_DTM, COALESCE(B.CURRENT_LOC, A.CURRENT_LOC) CURRENT_LOC, A.FROM_LOC
FROM MYTAB A
LEFT JOIN MYTAB B ON B.FROM_LOC = A.CURRENT_LOC AND A.CURRENT_LOC = 'TEMP-ONE'
WHERE A.FROM_LOC <> 'TEMP-ONE';

有没有一种方法可以编写一个查询，该查询将根据set critera合并行？

1 个答案: