How can I merge the columns from two tables into one output?

Question

I have two tables with similar information. Let\'s call them items_a and items_b. They should be one, but they are coming from different sources, s

Answer 1

SELECT col1,
  col2
FROM
  (SELECT rownum X,col_table1 FROM table1) T1
INNER JOIN
  (SELECT rownum Y, col_table2 FROM table2) T2
ON T1.X=T2.Y;