Question

select * from tblClientMealPlanHistories;
+----+---------+----------+--------+--------+---------------------+---------------------+-----------------+-----------+-------------+
| id | serving | ClientId | MealId | FoodId | createdAt           | updatedAt           | tblMasterFoodId | tblMealId | tblClientId |
+----+---------+----------+--------+--------+---------------------+---------------------+-----------------+-----------+-------------+
|  1 |       2 |        1 |      7 |      5 | 2017-07-14 10:10:40 | 2017-07-14 10:10:40 |            NULL |      NULL |        NULL |
|  2 |       3 |        1 |      7 |      9 | 2017-07-14 10:10:40 | 2017-07-14 10:10:40 |            NULL |      NULL |        NULL |
|  3 |       2 |        4 |      5 |      7 | 2017-07-14 10:11:10 | 2017-07-14 10:11:10 |            NULL |      NULL |        NULL |
|  4 |       1 |       10 |      1 |      7 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
|  5 |       3 |       10 |      1 |      9 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
|  6 |       4 |       10 |      1 |     10 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
|  7 |       2 |       10 |      2 |      7 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
|  8 |       3 |       10 |      3 |      9 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
|  9 |       3 |       10 |      3 |      4 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
| 10 |       2 |       10 |      7 |      4 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
| 11 |       2 |       10 |      7 |      8 | 2017-07-14 10:15:40 | 2017-07-14 10:15:40 |            NULL |      NULL |        NULL |
+----+---------+----------+--------+--------+---------------------+---------------------+-----------------+-----------+-------------+


 select distinct createdAt  from tblClientMealPlanHistories;
+---------------------+
| createdAt           |
+---------------------+
| 2017-07-14 10:10:40 |
| 2017-07-14 10:11:10 |
| 2017-07-14 10:15:40 |
+---------------------+

Answer 1

如果要查找在同一时间戳创建的所有ID，可以在group by字段上使用group_concat子句与id。

示例：

select createdAt
     , group_concat( id ) as ids
  from tblClientMealPlanHistories
 group by createdAt
 order by createdAt

输出可能如下所示：

+---------------------+-------------------+
| createdAt           | ids               |
+---------------------+-------------------+
| 2017-07-14 10:10:40 | 1,2               |
| 2017-07-14 10:11:10 | 3                 |
| 2017-07-14 10:15:40 | 4,5,6,7,8,9,10,11 |
+---------------------+-------------------+

我想要不同的createdAt以及id与不同的createdAt列

1 个答案: