#quick read to see what the file looks like

data <- read.table(file = "household_power_consumption.txt", nrow = 10, head=TRUE)

#load sql package

library("sqldf")

require("sqldf")

#sql statement to get desired rows

SQL <- "SELECT * FROM file WHERE Date = '1/2/2007' OR Date = '2/2/2007'"

file <- "household_power_consumption.txt"

data <- read.csv.sql(file, sql = SQL, sep=";")

data2 <- read.csv.sql(file, sql = SQL, sep=";")

#######################################plot 4##############################################

png("plot4.png", width=480, height=480)

#set up 4x4 plot

par(mfrow = c(2,2), mar = c(4,4,2,1), oma = c(0,0,2,0))

#topleft

plot(data2$Days, data2$Global_active_power,

type="l",

xlab="",

ylab="Global Active Power")

#topright

plot(data2$Days, data2$Voltage, type="l", col="black", ylab="Voltage", xlab="datetime")

#bottomleft

plot(data2$Days, data2$Sub_metering_1, type="l", col="black", ylab="Energy sub mettering", xlab="")

lines(data2$Days, data2$Sub_metering_2, type="l", col="red")

lines(data2$Days, data2$Sub_metering_3, type="l", col="blue")

legend("topright", lty=1,

col=c("black", "red", "blue"),

legend=c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"))

#bottomright

plot(data2$Days, data2$Global_reactive_power, type="l", col="black",

ylab="Global_reactive_power",

xlab="datetime")

dev.off()

dev.copy(png, file = "plot4.png")