How to summarize a lot of fields with mvappend

[takeru]

I am trying to find the standard deviation from the postfix log.
I assume the following search sentence.

index=postfix earliest=-50d
| timechart span=1d count by fromaddress
| eval readable_time=strftime(_time, "%Y-%m-%d ")
| fields - NULL OTHER _time _span _spandays
| transpose 50
| rename "row " as day
| eval mvfield=mvappend(day1,day2,day3,day4,day5............)
| stats avg(mvfield) as avg stdev(mvfield) as std by column

Is there a way to more easily define day 1 to day 50?
| eval mvfield=mvappend(day1,day2,day3,day4,day5............)

[somesoni2 · Accepted solution]

Give this a try

index=postfix earliest=-50d
| timechart span=1d count by fromaddress
| eval readable_time=strftime(_time, "%Y-%m-%d ")
| fields - NULL OTHER _time _span _spandays
| transpose 50
| rename "row " as day
| eval mvfield=null() | foreach day* [eval mvfield=mvappend(mvfield,'<<FIELD>>')]
| stats avg(mvfield) as avg stdev(mvfield) as std by column

[somesoni2]

Also, try this

index=postfix earliest=-50d
 | timechart span=1d count by fromaddress
 | eval readable_time=strftime(_time, "%Y-%m-%d ")
 | fields - NULL OTHER _time _span _spandays
| untable readable_time column valuefield
| stats avg(valuefield) stdev(valuefield) by column

[takeru]

The answer I was hoping for
Thank you!