I am using MySQL 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
```
And the other table represents 2020 Revenue
```
Week Name 2020 Revenue
1 Paul 554
1 Nick 200
2 Sam 400
```
I want the output be:
```
Week Name 2019 Revenue 2020 Revenue
1 Paul 576356 554
1 Nick 246564 200
2 Sam 426547265 400
```
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