merging sales from different sources

Hello 

i have my total sales from feb 2017 till this date 2018 on  my sql server. 

i also have my sales from jan 2017 only in excel. 

im trying to merger the total sales fileds from the diferent tables ( sql & excel) [adding jan 2017 sales from excel to 2017 sales] where my primamry key would be the sales man name since the sales people exists in both tables. 

what is the best way to combines the total sales taking into consideration the dates from 2017 and 2018

thanks alot