** MySql **为每个GroupId选择行之后

Question

我如何为每个grp_id 2行拥有： 当前unix时间戳行之前和之后，

+---------+--------------------+------------+-------+
| id      |             grp_id |     utimes | value |
+---------+--------------------+------------+-------+
| 4156187 |               5282 | 1455663600 | 15897 |
| 4159888 |               5282 | 1455630000 | 26998 |*
| 4156190 |               5282 | 1455676200 | 28497 |
| 4156186 |               5282 | 1455661800 | 14097 |
| 4156183 |               5282 | 1455652800 |  5097 |
| 4156184 |               5282 | 1455656400 |  8697 |
| 4156185 |               5282 | 1455660000 | 12297 |
| 4156182 |               5282 | 1455651000 |  3297 |*
| 4163311 |               7216 | 1455693000 | 45297 |
| 4163275 |               7203 | 1455681600 | 33897 |
| 4163309 |               7214 | 1455697800 | 50097 |
| 4163308 |               7214 | 1455696000 | 48297 |
| 4163307 |               7214 | 1455694200 | 46497 |
| 4163306 |               7214 | 1455692400 | 44697 |
| 4163305 |               7214 | 1455690600 | 42897 |
| 4163304 |               7214 | 1455688800 | 41097 |
| 4151121 |               4356 | 1455703200 | 55497 |
| 4163271 |               7205 | 1455685500 | 37797 |
| 4163272 |               7205 | 1455687000 | 39297 |
| 4163269 |               7205 | 1455684900 | 37197 |
| 4163273 |               7205 | 1455687300 | 39597 |
| 4163264 |               7206 | 1455674400 | 26697 |
| 4163270 |               7205 | 1455685200 | 37497 |
+---------+--------------------+------------+-------+

Example:
unix-timestamp : 1455647703

+---------+--------------------+------------+-------+
| id      |             grp_id |     utimes | value |
+---------+--------------------+------------+-------+
| 4159888 |               5282 | 1455630000 | 26998 |
| 4156190 |               5282 | 1455651000 | 28497 |
| 4159889 |               XYZ  | 1455630000 | 26998 |
| 4156191 |               XYZ  | 1455651000 | 28497 |
| 4159883 |               ABC  | 1455630000 | 26998 |
| 4156195 |               ABC  | 1455651000 | 28497 |
+---------+--------------------+------------+-------+

谢谢！

Answer 1

您可以使用LEFT JOIN操作执行此操作。 ON子句包含＆＃39;业务逻辑＆＃39;：

SELECT t1.*
FROM mytable AS t1
LEFT JOIN mytable AS t2 
   ON t1.grp_id = t2.grp_id 
      AND 
     ((t1.utimes < 1455647703 AND t2.utimes < 1455647703 AND t2.utimes > t1.utimes)
       OR
      (t1.utimes > 1455647703 AND t2.utimes > 1455647703 AND t2.utimes < t1.utimes))
WHERE t1.grp_id = 5282 AND t2.id IS NULL

Demo here