DML-select-Union and Union all:

nUsing union you can combine two or more select statements

nYou can use union to eliminate duplicates and union all to retain duplicates

Syntax:

SELECT column_name(s) FROM table_name1
UNION or UNION ALL

SELECT column_name(s) FROM table_name2

Query:

SELECT Empname FROM Emptbl1

UNION or UNION ALL

SELECT Empname FROM Emptbl2