As there are only four columns and two tables, it looks easy to perform union in this way. If we have more than 20 columns(unordered in two or more tables), it will get real tough to make calculation like this. Is there any other simple way?
Thanks for providing the workaround with UNION(SELECTCOLUMNS(),SELECTCOLUMNS()). I need to union two tables plus a third one which did not have all the columns of the first two. So I added "dummy" empty columns with two quotes or BLANK() for values. It worked!