I would like to merge 2 tables keeping all rows in both tables like doing a left and a right join at the same t开发者_StackOverflow中文版ime. 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);
Since MySQL doesn't have a FULL OUTER JOIN, you can emulate it since MySQL 4 using UNION:
SELECT t1.fruit, t1.number, t2.number
FROM Table1 AS t1
LEFT JOIN Table2 AS t2 ON t2.fruit = t1.fruit
UNION
SELECT t2.fruit, t1.number, t2.number
FROM Table1 AS t1
RIGHT JOIN Table2 AS t2 ON t2.fruit = t1.fruit
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));
insert into mergetable
(fruit, number_table1, number_table2)
select t1.fruit, t1.number, t2.number
from table1 t1
left join table2 t2
on t1.fruit = t2.fruit
union
select t2.fruit, t1.number, t2.number
from table2 t2
left join table1 t1
on t2.fruit = t1.fruit
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