SQL 以分钟为单位计算平均下载量

Question

我无法从以下 ANSI-92 SQL 或 Impala SQL标准。

login_id ,开始时间戳 ,停止时间戳 ,download_bytes
abc@fcc.com, 2015-12-31 23:59:50, 2016-01-01 00:00:20, 438.0
abc@fcc.com, 2016-01-01 00:00:28, 2016-01-01 00:01:13, 2190.0
abc@fcc.com, 2016-01-01 00:01:21, 2016-01-01 00:01:54, 876.0
abc@fcc.com, 2016-01-01 00:01:59, 2016-01-01 00:02:34, 1168.0
abc@fcc.com, 2016-01-01 00:02:43, 2016-01-01 00:03:34, 1179.0

粗体显示的时间共享starttimestamp 和stoptimestamp 的时间space（以分钟为单位）。如何获得

中的平均下载量

00:00:00 分钟 ( 00:00:20 - 00:00:28 )
00:01:00 分钟 ( 00:01:13 - 00:01:21 )
00:02:00 分钟 ( 00:02:34 - 00:02:43 )

等等。

有什么建议吗？非常感谢您！

此致，

波兹

Answer 1

select
    (unix_timestamp(stoptimestamp)-unix_timestamp(starttimestamp)) / 60.0 diff_minutes
from your_table

使用 unix_timestamp() 计算以秒为单位的差异，然后根据您希望结果的精度除以 60 或 60.0。

要计算多行的平均下载量，您需要使用 SUM() 来聚合字节并计算时间单位。 您可能希望使用秒数进行初始计算，然后除以 60.0

以下示例是为 SQL 服务器编写的，因为我没有 Impala 可以使用

declare  @mytable table
    ([login_id] varchar(11), [starttimestamp_] datetime, [stoptimestamp_] datetime, [download_bytes] decimal(12,1))
;

INSERT INTO @mytable
    ([login_id], [starttimestamp_], [stoptimestamp_], [download_bytes])
VALUES
    ('abc@fcc.com', '2015-12-31 23:59:50', '2016-01-01 00:00:20', 438.0),
    ('abc@fcc.com', '2016-01-01 00:00:28', '2016-01-01 00:01:13', 2190.0),
    ('abc@fcc.com', '2016-01-01 00:01:21', '2016-01-01 00:01:54', 876.0),
    ('abc@fcc.com', '2016-01-01 00:01:59', '2016-01-01 00:02:34', 1168.0),
    ('abc@fcc.com', '2016-01-01 00:02:43', '2016-01-01 00:03:34', 1179.0)
;

select
  sum(download_bytes) sum_bytes
, sum(datediff(second,starttimestamp_,stoptimestamp_)) sum_time_unit
, sum(download_bytes)/sum(datediff(second,starttimestamp_,stoptimestamp_)) avg_bytes_sec
, (sum(download_bytes)/sum(datediff(second,starttimestamp_,stoptimestamp_)))/60.0 avg_bytes_min
from @mytable
-- WHERE ...
-- GROUP BY ...

+===========+===============+===============+===============+
| sum_bytes | sum_time_unit | avg_bytes_sec | avg_bytes_min |
+===========+===============+===============+===============+
| 5851      | 194           | 30.159793     | 0.502663      |
+-----------+---------------+---------------+---------------+

参见：https://data.stackexchange.com/Whosebug/query/576857/sql-to-calculate-average-download-in-minutes

SQL 以分钟为单位计算平均下载量

SQL to calculate average download in minutes

sql

impala