MySQL: FULL OUTER JOIN - How do I merge one column?

Question

I have a question regarding a FULL OUTER JOIN in MySQL. I have two (or more tables):

table1      table2
id  value   id  value2
1   a       1   b
2   c       3   d         


        

Answer 1

For what I think you are trying to do, I would suggest using a FULL OUTER JOIN instead:

SELECT ISNULL(t1.id, t2.id) AS id, t1.value1, t2.value2
FROM table1 t1
FULL OUTER JOIN table2 t2 ON t1.id = t2.id