you would need to see if in your table 1 the data matches your table2 so you can add a left join.
since table 2 will be joined with table 1 and if the data in table 2 do not match those in table 1, your data will be shown as null if the data does not coincide and otherwise the data will show the data that coincide.
load * from tab1;
left join (Table 1)
load * from tab2;
I think it would be more correct to concatenate something like this: