Question

I would like to merge 2 tables keeping all rows in both tables like doing a left and a right join at the same time.
See example below. Column ‘fruit’ is common to both tables and I want to list the number of fruit in both tables. Also a particular fruit may appear in one table but not the other.
Can anyone help? Thanks.

TABLE1                    TABLE2                
fruit, number             fruit, number         
-------------             -------------         
apples,  1                apples,   10          
pears,   2                oranges,  30          


MERGED TABLE (this is the result I'm after:
fruit, number_table1, number_table2
--------------------------------------
apples,     1,      10
pears,      2,      -
oranges,    -,      30

And here is the code to create the tables if you need to try it out….

CREATE TABLE table1 (fruit CHAR(10) NOT NULL, number INT(10) NOT NULL);
CREATE TABLE table2 (fruit CHAR(10) NOT NULL, number INT(10) NOT NULL);
insert into table1 (fruit, number) values ('apples', 1), ('pears', 2);
insert into table2 (fruit, number) values ('apples', 10), ('oranges', 30);

Answer 1

Here is a solution using UNION:

(select table1.fruit fruit, table1.number number1, table2.number number2 from table1 left join table2 using (fruit)) union (select table2.fruit fruit, table1.number number1, table2.number number2 from table2 left join table1 using (fruit));