获取开始和结束时间 MYSQL

Question

我正在尝试检索可以确定开始和结束日期的数据并查看 petname 的变化间隔

这是我的示例数据。

这是我的预期输出

我试过这样查询

    SELECT 
    `line`, `Petname`, MIN(`start date`), MAX(`end date`)
FROM
    `tablename`
WHERE
    timestamp BETWEEN '2020-07-01 00:00:00' AND NOW() group by petname

但我的输出 return 是这样的

Answer 1

我没有得到你 table 的创建 sql，因此我创建了一个只是为了测试。以下是我的验证table。可能和你的不一样，请根据自己的情况修改table.

+----+---------+------------+------------+
| id | petname | start_date | end_date   |
+----+---------+------------+------------+
|  1 | FKN92B  | 2020-07-01 | 2020-07-02 |
|  2 | FKN92B  | 2020-07-02 | 2020-07-04 |
|  3 | FKN8LD  | 2020-07-04 | 2020-07-05 |
|  4 | FKN8LD  | 2020-07-07 | 2020-07-08 |
|  5 | FKN92B  | 2020-07-11 | 2020-07-12 |
|  6 | FKN92B  | 2020-07-12 | 2020-07-14 |
|  7 | FKN8LD  | 2020-07-08 | 2020-07-09 |
|  8 | FKN8LD  | 2020-07-11 | 2020-07-11 |
+----+---------+------------+------------+
8 rows in set (0.00 sec)

SQL如下，请试一试，如有问题请告诉我：

mysql> SET @lastpetname := null;
Query OK, 0 rows affected (0.00 sec)

mysql> SET @groupnum := 0;
Query OK, 0 rows affected (0.00 sec)

mysql> select petname, min(start_date), max(end_date)
    -> from
    ->     (SELECT
    ->             case
    ->                when @lastpetname is null then @groupnum := @groupnum + 1
    ->                when @lastpetname != petname > 0 then @groupnum := @groupnum + 1
    ->                else @groupnum := @groupnum
    ->             end as group_num,
    ->             @lastpetname := petname as petname,
    ->             `start_date`,
    ->            `end_date`
    ->     from `petlog`) t
    -> group by group_num;
+---------+-----------------+---------------+
| petname | min(start_date) | max(end_date) |
+---------+-----------------+---------------+
| FKN92B  | 2020-07-01      | 2020-07-04    |
| FKN8LD  | 2020-07-04      | 2020-07-08    |
| FKN92B  | 2020-07-11      | 2020-07-14    |
| FKN8LD  | 2020-07-08      | 2020-07-11    |
+---------+-----------------+---------------+
4 rows in set (0.00 sec)

获取开始和结束时间 MYSQL

Getting The Start and End Time MYSQL

mysql

mysql-workbench

workbench