TO CONNECT:
library("RPostgreSQL")
drv <- dbDriver("PostgreSQL")
con <- dbConnect(drv, dbname="postgres",host="dataport.pecanstreet.org",port=5434,user="username",password="password")

GETS EVERYTHING FROM THIS TABLE:
myTable <- dbReadTable(con, c("university", "electricity_egauge_15min"))

SELECT CERTAIN VALUES FROM A TABLE:
data <- dbGetQuery(con, "SELECT * from university.weather WHERE localhour BETWEEN '01-01-2015' AND '02-01-2015'")
data1 <- dbGetQuery(con, "SELECT * from university.electricity_egauge_15min WHERE dataid=9737 AND local_15min BETWEEN '01-01-2015' AND '02-01-2015'")
data2 <- dbGetQuery(con, "SELECT * from university.electricity_egauge_15min WHERE dataid in (18 ,35 ,114 ,370) AND local_15min BETWEEN '01-01-2015' AND '02-01-2015'")


TO SAVE DATAFRAME TO DESKTOP:
write.csv(data, file="C:\\Users\\<<username>>\\Desktop\\test.csv")

MERGE DATA FRAMES INTO ONE BIG DATASET (WITH A HEADER LINE)
data1 = read.csv("C:\\Users\\<<username>>\\Desktop\\test.csv", header=T)
data2 = read.csv("C:\\Users\\<<username>>\\Desktop\\test2.csv", header=T)
fulldata = merge(data1, data2)


TO DISCONNECT:
dbDisconnect(con)