how to compare if 2 columns in pandas dataframe are equal then update the rest of the dataframe
demand_hist_sku_date = demand_history['Pyramid Key'] + demand_history['FCST_YR_PRD']
azlog_3_sku_date = azlog_3['Pyramid Key']+ azlog_3['FCST_YR_PRD']
demand_history.loc[demand_hist_sku_date.isin(azlog_3_sku_date), 'DMD_ACTL_QTY' ] = azlog_3['DMD_ACTL_QTY']
I have 2 pandas dataframes and trying to compare if 2 of their columns are equal then update the rest of the dataframe if not append the new data so concat or something like that .
i tried this amongst other stuff

if demand_history[['Pyramid Key','FCST_YR_PRD']] == azlog_3[['Pyramid Key','FCST_YR_PRD']]:
demand_history['DMD_ACTL_QTY'] ==azlog_3['DMD_ACTL_QTY']