Hi:

One option is to read your data frame into R and then use your SQL code in
conjunction with the sqldf package. It uses SQLite as its engine.

HTH,
Dennis


On Mon, Sep 27, 2010 at 4:29 AM, Xin Zhang <xin.zhang@gmail.com> wrote:

> Suppose I have the following data frame (df):
>
> Year    Price
> -------------------
> 2001    10
> 2002    20
> 2003    30
>
> I would like to produce another data frame like this:
>
> a.Year    a.Price    b.Year    b.Price
> ----------------------------------------------------
> 2002    20    2001    10
> 2003    30    2001    10
> 2003    30    2002    20
>
> In SQL, this can be done as
>
> select a.*, b.*
> from df as a, df as b
> where a.Year > b.Year
>
> How do I do this efficiently in R?
>
> Many thanks.
>
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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