DB2 a reference to column is ambigous

Question

I want to write a select to combine two result sets without using union.

TABLE_A

ID	VALID
1	true
2	false

TABLE_B

ID	VALID
44	true
55	false

Can I make a select like this without using union

SELECT ID
FROM TABLE_A, TABLE_B

With union...

SELECT ID
FROM TABLE_A
UNION
SELECT ID
FROM TABLE_B
UNION

expected result...

ID	VALID
1	true
2	false
44	true
55	false