http://elreal.com.ni/?sypermen=lal%C3%ADn-online-dating&399=f8 Connecting PostgreSQL from R using RdbiPgSQL
library(RdbiPgSQL) conn <- dbConnect(PgSQL(), host="localhost", dbname="my_database", user="my_user", password="my_secret_password") res <- dbSendQuery(conn, "select * from prices where item_id = 29") mydata <- dbGetResult(res) ... dbDisconnect(conn)
How to select the first/least/max row per group in SQL
A nice explanation about the subject. Easy to understand.
http://www.xaprb.com/blog/2006/12/07/how-to-select-the-firstleastmax-row-per-group-in-sql/
Find duplicates in MySQL
SELECT col1, col2, count(col3) FROM t1 GROUP BY col1, col2 HAVING count(col3) > 1
Adapted from
http://support.microsoft.com/default.aspx?scid=kb;en-us;139444