spdr s&p 500 trust (bats:spy) tradre

study(title="Volume", shorttitle="Vol", precision=0)
showMA = input(true)
plot(volume, color = open > close ? red : green, style=columns, title="Volume MA", transp=65)
plot(showMA ? sma(volume,20) : na, style=area, color=blue, title="Volume", transp=65)