Battery % time charging
90 t1 yes
91 t2 yes
95 t3 no
89 t4 no
87 t5 no
80 t6 no
78 t7 yes
85 t8 yes
50 t9 no
40 t10 no
38 t11 no
20 t12 yes
I want to calculate battery depletion rate as : change in battery / time taken
This should be calculated for ALL the windows when charging is 'no' (sandwiched in between 2 "yes"), and then the average of those rates should be taken.
So, for this dataset it should be:
95 - 80 / t6 - t3 = rate 1
50 - 38 / t11 - t9 = rate 2
average rate = ( rate 1 rate 2 ) / 2
Please note there can be more than 2 windows of no's in the data
Here is my current code -
select ((max(battery_Percentage) - min (battery_Percentage)) / NULLIF(Extract(epoch FROM (max(time) - min(time))/3600),0)) as rate_of_battery_decline
from table
where
table.charging = 'no'
but this is not taking into account windows of no's in between the yes's as I want. Please help.
CodePudding user response:
You have to separate the runs between the charging = 'yes'
blocks:
with discharge_intervals as (
select battery_pct, tstamp,
sum((charging = 'yes')::int) over (order by tstamp) as ival_number,
charging = 'no' as keep
from cstats
), interval_rates as (
select ival_number,
(max(battery_pct) - min(battery_pct))
/ extract(epoch from max(tstamp) - min(tstamp)) as ival_rate
from discharge_intervals
where keep
group by ival_number
)
select avg(ival_rate)
from interval_rates;