How to find standard deviation in R using sqldf package?

Question

All i can do with sqldf package is calculate " avg" "count " and "sum". Can i define my own function for standard deviation?

It is really necessary for me to calculate Standard deviation using sqldf only.

The extension functions listed under `extension-functions.c` at the bottom of http://www.sqlite.org/contrib are all available. — G. Grothendieck, Feb 08 '16 at 15:31

score 5 · Accepted Answer · answered Feb 08 '16 at 12:30

5

The function for standard deviation is stdev

d1 = data.frame(x=runif(10))
sqldf("select stdev(x) from d1")

answered Feb 08 '16 at 12:30

Pekka

You just made me realize how stupid of me it was to ask this question at the first place. – JAS Feb 08 '16 at 13:38
1

Not stupid. I found my way here as well. The native R function for standard deviation is 'sd', Oracle SQL uses STDDEV, MS SQL does use STDEV, but it also has STDEVP. ASCII SQL uses STDDEV_POP....Judging by the sample, there are a number of reasonable names that could have been used for the standard deviation, after trying some, this is a good site to ask for help. – VictorZurkowski Mar 06 '17 at 16:38

1 Answers1