First Query:-
In this case, you have to write a SQL Query using SQL JOIN which return the data which is not common to these two tables A& B as shown in the shaded part in 1st figure.
Second Query:-
In this case, you have to write a SQL Query using SQL JOIN which will return the data from table A which is not in the table B as shown as shaded part in 2nd figure.
Third Query:-
In this case, you have to write a SQL Query using SQL JOIN which will return the data from table B which is not in the table A as shown as shaded part in 3rd figure.