If you have TABLE A with these columns (I put the data type in parenthesis, they are not actually part of the table name):
LAST_NAME(TEXT), FIRST_NAME(TEXT), MIDDLE_NAME(TEXT), DATE_OF_BIRTH(DATE), and TABLE B with these columns:
LAST_NAME(TEXT), FIRST_NAME(TEXT), MIDDLE_NAME(TEXT), DATE_OF_EMPLOYMENT(DATE) and you ran this UNION query:
Select A.* From A UNION Select B.* From B;
* What column name would the 4th column get?
* Would the data in the 4th column have much "meaning" or "context" at that point?