Filter according to the latest data
On Fri, Feb 1, 2013 at 8:05 AM, nalluri pratap <pratap_stat at yahoo.co.in> wrote:
library(sqldf)
sqldf("select *
from k1
group by No
having max(Date)")
HAVING is only used to select groups and only works by chance in this example but if the data were to change then it would likely not work. Try this instead. It makes use of an sqlite-specific feature that guarantees that when MAX is used in a GROUP BY that the other columns will be from the same row:
sqldf("select ID, No, Change, max(Date) Date from k1 group by No")
ID No Change Date 1 D 111 final 2013-01-12 2 C 123 bug fixed 2013-01-17 -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com