outer join where left is null python r_suffix code example
Example: join on column pandas
# df1 as main df and use the feild from df2 and map it into df1
df1.merge(df2,on='columnName',how='left')
# df1 as main df and use the feild from df2 and map it into df1
df1.merge(df2,on='columnName',how='left')