[R] help with SQL, how can i use functions in sql (pkg :sqldf)

[Gabor Grothendieck]

sqldf also works with MySQL (although its been less tested with
that) and MySQL does support a wider range of functions than
sqlite:

http://dev.mysql.com/doc/refman/5.0/en/func-op-summary-ref.html

On Tue, Sep 16, 2008 at 10:18 AM, Tom Willems <Tom.Willems at var.fgov.be> wrote:
> Dear R ussers ,
>
> I was trying to summaryse data with sql, from the sqldf pkg.
>
> it seemed like a promessing solution, yet all i can do in this is
> calculate  " avg"  "count " and "sum".
>
> where i d like to use confidence intervals  and standard deviation as wel.
>
> now i was trying to find  a solution my self , but the closest i got was "
> sqlite3_create_function16"
> explained on
>                          http://www.sqlite.org/c3ref/create_function.html
> sadely i don't understand much of the explanation.
>
> Now i hoped sombody could give me an other SQL solution for this.
>
> the function i hoped to use is this one.
>
>> mean.CI <-
> function (X,na.rm=T)
>    {   names(X)<-NULL
>        if (is.vector(X))  {nn <- length(X)}
>        else   {nn <- nrow(X)}
>        NAs <- sum(is.na(X))
>        n <- nn-NAs
>            if (na.rm)
>        avg  <- mean(X,na.rm=T)
>        Sd  <- sd(X,na.rm=T)
>        Var  <- var(X,na.rm=T)
>        if (is.matrix(X)) {
>            apply(X, 2, sd, na.rm = T) }
>        else if (is.vector(X))  {
>           confin <-qt(0.975,df=n-1)*(sd(X, na.rm = T)/sqrt(n))}
>        else if (is.data.frame(X)){
>           confin <-qt(0.975,df=n-1)*((sapply(X, sd, na.rm = T))/sqrt(n))}
>        else {confin <- qt(0.975,df=n-1)*(sd(as.vector(X), na.rm =
> T))/sqrt(n)}
>       out <-round (c( avg-confin ,avg+confin) ,digits=3)
>       out
>    }
>
>
> kind regards,
> Tom
>
>
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