join two dataset on two columns sql domo

Question

I am using MySQL with DOMO. I have two tables that I want to join on both columns. My data looks like the following:

The first table represents 2019 Revenue

Week        Name           2019 Revenue
1            Paul             576356
1            Nick             246564
2            Sam              426547265
2            Frank            5436

And the other table represents 2020 Revenue

Week        Name           2020 Revenue
1            Paul             554
1            Nick             200
2            Sam              400
2            Frank            500

I want the output be:

Week        Name           2019 Revenue         2020 Revenue
1            Paul             576356                  554
1            Nick             246564                  200
2            Sam              426547265               400
2            Frank            5436                    500

I have tried the following:

SELECT
`Week`,
`Advertiser`,
`2019 Revenue`
from `2019` as a
left join `2020` as b
    on a.`Week` = b.`Week`
    and a.`Advertiser` = b.`Advertiser`

Error message: SQL constraint violated: Column 'Week' in field list is ambiguous

Answer 1

The answer should be obvious. But the solution is that you get into the habit of always qualifying column names in queries:

SELECT a.Week, a.Advertiser, a.`2019 Revenue`, b.`2020 Revenue`
from `2019` a left join
     `2020` b
     on a.Week = b.Week and   
        a.Advertiser = b.Advertiser;