在BigQuery SQL中,可以使用窗口函数和LAG函数来实现连续行计算中减少剩余分钟计数器的功能。下面是一个包含代码示例的解决方法:
假设有一个名为logs
的表,其中包含以下字段:
event_time
:事件发生的时间戳(TIMESTAMP类型)event_type
:事件类型(STRING类型)我们想要计算每个事件类型在连续的时间范围内剩余的分钟数。
首先,我们可以使用LAG函数来获取前一行的事件类型和事件时间:
SELECT
event_time,
event_type,
LAG(event_type) OVER (ORDER BY event_time) AS prev_event_type,
LAG(event_time) OVER (ORDER BY event_time) AS prev_event_time
FROM
logs
然后,我们可以计算当前行与前一行之间的时间差:
SELECT
event_time,
event_type,
prev_event_type,
prev_event_time,
TIMESTAMP_DIFF(event_time, prev_event_time, MINUTE) AS time_diff
FROM (
SELECT
event_time,
event_type,
LAG(event_type) OVER (ORDER BY event_time) AS prev_event_type,
LAG(event_time) OVER (ORDER BY event_time) AS prev_event_time
FROM
logs
)
接下来,我们可以使用SUM函数和窗口函数来计算连续的事件类型出现的次数:
SELECT
event_time,
event_type,
prev_event_type,
prev_event_time,
time_diff,
SUM(CASE WHEN event_type = prev_event_type THEN 0 ELSE 1 END) OVER (ORDER BY event_time) AS counter
FROM (
SELECT
event_time,
event_type,
LAG(event_type) OVER (ORDER BY event_time) AS prev_event_type,
LAG(event_time) OVER (ORDER BY event_time) AS prev_event_time,
TIMESTAMP_DIFF(event_time, LAG(event_time) OVER (ORDER BY event_time), MINUTE) AS time_diff
FROM
logs
)
最后,我们可以计算剩余的分钟计数器:
SELECT
event_time,
event_type,
prev_event_type,
prev_event_time,
time_diff,
counter,
SUM(time_diff) OVER (ORDER BY event_time) - counter AS remaining_counter
FROM (
SELECT
event_time,
event_type,
prev_event_type,
prev_event_time,
time_diff,
SUM(CASE WHEN event_type = prev_event_type THEN 0 ELSE 1 END) OVER (ORDER BY event_time) AS counter
FROM (
SELECT
event_time,
event_type,
LAG(event_type) OVER (ORDER BY event_time) AS prev_event_type,
LAG(event_time) OVER (ORDER BY event_time) AS prev_event_time,
TIMESTAMP_DIFF(event_time, LAG(event_time) OVER (ORDER BY event_time), MINUTE) AS time_diff
FROM
logs
)
)
通过以上代码,我们可以计算出每个事件类型在连续的时间范围内剩余的分钟数。