It works :) Thanks so much! I tried searching a lot but I guess i missed
this fact!
On Thu, Aug 14, 2014 at 4:35 PM, Gabor Grothendieck <ggrothendi...@gmail.com
> wrote:
> On Thu, Aug 14, 2014 at 3:47 PM, Sneha Bishnoi <sneha.bish...@gmail.com>
> wrote:
> > Hi All!
> >
> > I am trying to increment date column of data frame so as to merge it with
> > another data frame using sqldf:
> > my query is :
> > merge<-sqldf("select m.* ,e.* from mdata as m left join event as e on
> > date(m.Datest,'+1 day')=e.Start")
> >
> > The query returns null for all columns related to event table.
> > When I investigated further with query :
> > sqldf("select date(Datest,'+1 day')") from eventflight;")
> > gives me -ve valued dates like : -4671-02-15
> >
> > However this works:
> > sqldf("select date(('2009-05-01'),'+1')")
> >
> > Dataframes are as follows:
> > mdata :
> > LOS Arrivals BookRange Datest
> > 1 1283 0-4 2009-05-01
> > 1 1650 0-4 2009-05-08
> > 1 1302 5-9 2009-05-15
> >
> > event:
> > Event.Name Event.location Start End
> > Birthday Texas (US) 2009-05-02 2009-05-03
> > Anni Texas (US) 2009-05-09 2009-01-11
> >
> > What am I doing wrong?
>
> This is a FAQ. See #4 here: http://sqldf.googlecode.com .
>
> The SQLite date function assumes its argument is a timestring but R
> "Date" class variables are transferred to SQLite as days since
> 1970-01-01 so just add 1.
>
> sqldf("select * from mdata as m left join event on Datest+1 = Start")
>
>
>
> --
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com
>
--
Sneha Bishnoi
+14047235469
H. Milton Stewart School of Industrial & Systems Engineering
Georgia Tech
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