Question

使用以下数据......

+--------------+--------+---------------+-----------------+----------------+
| EQUIPMENT_ID | CML_ID | INSPECTION_NO | INSPECTION_DATE | WALL_THICKNESS |
+--------------+--------+---------------+-----------------+----------------+
| B1000-V001   | 1      | 1             | 1/01/2016       | 10             |
| B1000-V001   | 1      | 2             | 2/01/2016       | 9              |
| B1000-V001   | 1      | 3             | 3/01/2016       | 3              |
| B1000-V001   | 1      | 4             | 4/01/2016       | 7              |
| B1000-V001   | 1      | 5             | 5/01/2016       | 5              |
| B1000-V001   | 1      | 6             | 6/01/2016       | 4              |
| B1000-V001   | 1      | 7             | 7/01/2016       | 4              |
| B1000-V001   | 1      | 8             | 8/01/2016       | 8              |
| B1000-V001   | 1      | 9             | 9/01/2016       | 17             |
| B1000-V001   | 1      | 10            | 10/01/2016      | 5              |
| B1000-X123   | 5      | 1             | 1/01/2016       | 2              |
| B1000-X123   | 5      | 2             | 2/01/2016       | 8              |
| B1000-X123   | 5      | 3             | 3/01/2016       | 4              |
| B1000-X123   | 5      | 4             | 4/01/2016       | 5              |
| B1000-X123   | 5      | 5             | 5/01/2016       | 7              |
| B1000-P789   | 3      | 1             | 1/01/2016       | 8              |
| B1000-P789   | 3      | 2             | 2/01/2016       | 7              |
| B1000-P789   | 3      | 3             | 3/01/2016       | 5              |
| B1000-P789   | 3      | 4             | 4/01/2016       | 1              |
| B1000-P789   | 3      | 5             | 5/01/2016       | 4              |
+--------------+--------+---------------+-----------------+----------------+

我希望以最快的方式产生以下结果......

+--------------+--------+---------------+-----------------+----------------+
| EQUIPMENT_ID | CML_ID | INSPECTION_NO | INSPECTION_DATE | WALL_THICKNESS |
| B1000-V001   | 1      | 10            | 10/01/2016      | 5              |
| B1000-P789   | 3      | 5             | 5/01/2016       | 4              |
| B1000-X123   | 5      | 5             | 5/01/2016       | 7              |
+--------------+--------+---------------+-----------------+----------------+

即。 GROUP BY EQUIPMENT_ID，CML_ID并始终返回与最大检验编号相关联的记录。

Answer 1

尝试以下查询。

    Select a.Equipment_ID, a.CML_ID, b.INSPECTION_NO,a.INSPECTION_DATE, a.WALL_THICKNESS
    from
    #YourTable a inner join
    (
    Select Equipment_ID, CML_ID, max(INSPECTION_NO)as INSPECTION_NO
    from #YourTable
    Group By Equipment_ID,CML_ID 
    ) b
    on a.Equipment_ID=b.Equipment_ID and a.CML_ID=b.CML_ID and a.INSPECTION_NO=b.INSPECTION_NO
    order by a.Equipment_ID

SQL_FIDDLE：DEMO

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MySQL - 返回每个数据组的最后记录

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