将分钟数据转换为数据库中的小时时如何删除和更新行

Question

这是帖子的继续 need database hourly data before two months

hostname              | cpuload | freedisk  | freemem |timestamp 
 localhost.localdomain | 0.15    | 136052    | 383660  | 2017-08-01 00:10:08 
 localhost.localdomain | 0.03    | 136492    | 383660  | 2017-08-01 00:20:08 
 localhost.localdomain | 0.01    | 133456    | 383660  | 2017-08-01 00:30:08 
 localhost.localdomain | 0.10    | 64544     | 383660  | 2017-08-01 00:40:08 
 localhost.localdomain | 0.01    | 68148     | 383660  | 2017-08-01 01:00:08

得到的输出是

hostname                cpuload     freedisk      freemem
-------------------------------------------------------------
localhost.localdomain   0.072500    117636.0000   383660.0000
localhost.localdomain   0.010000    68148.0000    383660.0000

我用过查询

SELECT t1.hostname
    ,avg(cpuload) AS cpuload
    ,avg(freedisk) AS freedisk
    ,avg(freemem) AS freemem
FROM table1 t1
WHERE t1.TIMESTAMP < current_timestamp - interval '42' day
GROUP BY date_format(t1.TIMESTAMP, '%Y%m%d%H');

在这里，我想将获得的结果插入到同一个表中，并删除我们进行操作的 2 个月前的数据。

请帮帮我

提前致谢

萨加雷迪

Answer 1

您可以使用insert-select 插入新生成的数据，如下所示。

insert into table1 
SELECT t1.hostname
    ,avg(cpuload) AS cpuload
    ,avg(freedisk) AS freedisk
    ,avg(freemem) AS freemem,
    date_format(t1.TIMESTAMP, '%Y-%m-%d %H')as timestamp
FROM table1 t1
WHERE t1.TIMESTAMP < current_timestamp - interval '42' day
GROUP BY date_format(t1.TIMESTAMP, '%Y%m%d%H');

插入后，表格如下所示。

hostname                cpuload    freedisk    freemem  timestamp
---------------------------------------------------------------------------
localhost.localdomain   0.15       136052      383660   01.08.2017 00:10:08
localhost.localdomain   0.03       136492      383660   01.08.2017 00:20:08
localhost.localdomain   0.01       133456      383660   01.08.2017 00:30:08
localhost.localdomain   0.10       64544       383660   01.08.2017 00:40:08
localhost.localdomain   0.01       68148       383660   01.08.2017 01:00:08
localhost.localdomain   0.07       117636      383660   01.08.2017 00:00:00
localhost.localdomain   0.01       68148       383660   01.08.2017 01:00:00

DEMO

然后您可以使用以下查询删除旧数据。

DELETE
FROM table1
WHERE TIMESTAMP NOT IN (
        SELECT TIMESTAMP
        FROM (
            SELECT date_format(t1.TIMESTAMP, '%Y-%m-%d %H:00:00') AS TIMESTAMP
            FROM table1 t1
            WHERE t1.TIMESTAMP < current_timestamp - interval '42' day
            GROUP BY date_format(t1.TIMESTAMP, '%Y%m%d%H')
            ) x
        );

请注意，由于您的表没有插入 timestamp 列或任何其他可以识别行的列，上述查询是在假设您的表不包含新生成的确切时间戳的情况下编写的行。

---

更新 1：

如果要删除特定时间段的数据，可以在下面的where子句中提及。

DELETE
FROM table1
WHERE TIMESTAMP NOT IN (
        SELECT TIMESTAMP
        FROM (
            SELECT date_format(t1.TIMESTAMP, '%Y-%m-%d %H:00:00') AS TIMESTAMP
            FROM table1 t1
            WHERE t1.TIMESTAMP < current_timestamp - interval '42' day
            GROUP BY date_format(t1.TIMESTAMP, '%Y%m%d%H')
            ) x
        )
    AND TIMESTAMP BETWEEN '2017-08-01 00:00:00'
        AND '2017-09-30 11:00:00';

希望这会给你一个想法:-)

DEMO