MYSQL:如何从表中提取以下数据？

Question

如何从下表中提取每天的第一个“StartAddress”。

结果一定是这样的。

+------------+---------------+--------------------+--------------------+
| Date       | SamplingStart | StartAddress       | StopAddress        |
+------------+---------------+--------------------+--------------------+
| 2016-02-22 | 08:00:00      | 26 Riverside Drive | 70 Piet Retief     |
| 2016-02-23 | 05:15:00      | Balizza            | Mars               |
+------------+---------------+--------------------+--------------------|

表格:

+------------+---------------+--------------------+--------------------+
| Date       | SamplingStart | StartAddress       | StopAddress        |
+------------+---------------+--------------------+--------------------+
| 2016-02-22 | 08:00:00      | 26 Riverside Drive | 70 Piet Retief     |
| 2016-02-22 | 09:00:00      | 10 Glen Drive      | 16 Olga Street     |
| 2016-02-22 | 10:00:00      | 66 Bremerhof       | 26 Bluewater Drive |
| 2016-02-22 | 11:00:00      | 7 New Street       | Walker Drive       |
| 2016-02-22 | 13:00:00      | Goodwood Street    | Blouberg           |
| 2016-02-22 | 15:00:00      | Marine Drive       | William Moffet     |
| 2016-02-22 | 18:00:00      | Jumanji            | Paterson           |
| 2016-02-23 | 07:00:00      | 25 Eazi Street     | 70 Kings Street    |
| 2016-02-23 | 07:20:00      | Cool Blue          | Pick n Pay         |
| 2016-02-23 | 05:15:00      | Balizza            | Mars               |
| 2016-02-23 | 20:15:00      | Neverland          | Club Shakes        |
| 2016-02-23 | 23:15:00      | Castros            | Stones             |
| 2016-02-23 | 14:45:00      | Seagate            | Ermelo             |
| 2016-02-23 | 16:30:00      | Mafikeng           | Goodwood           |
+------------+---------------+--------------------+--------------------+

Answer 1

试试这个:

SELECT 
    * 
FROM
    tbl
WHERE 
    (Date, SamplingStart) IN
    (
        SELECT tbl2.Date, MIN(tbl2.SamplingStart)
        FROM tbl tbl2
        WHERE tbl.Date = tbl2.Date
    );