how to merge Two datasets with different time ranges?

I have two datasets that look like this:

df1:

df2:

My date is in format period[M] for both datasets. I have tried using the df1.join(df2,how='outer') and (df2.join(df1,how='outer') commands but they don't add up correctly, essentially, in 2019-01, I have sales for 2020-03. How can I join these two datasets such that my output is as follows:

I have not been able to use merge() because I would have to merge with a combination of City and State and Date

You can outer-merge. By not specifying the columns to merge on, you merge on the intersection of the columns in both DataFrames (in this case, Date, City and State).

out = df1.merge(df2, how='outer').sort_values(by='Date')

Output:

      Date     City State  Quantity   Sales
0  2019-01  Chicago    IL      35.0     NaN
1  2019-01  Orlando    FL     322.0     NaN
4  2020-03  Chicago    IL       NaN    30.0
5  2020-03  Orlando    FL       NaN   319.0
2  2021-07  Chicago    IL     334.0   331.0
3  2021-07  Orlando    FL    4332.0  4000.0