Which statement is true regarding the UNION operator?
A.
The number of columns selected in all SELECT statements need to be the same
B.
Names of all columns must be identical across all SELECT statements
C.
By default, the output is not sorted
D.
NULL values are not ignored during duplicate checking
Explanation:
The SQL UNION query allows you to combine the result sets of two or more SQL SELECT
statements. It removes duplicate rows between the various SELECT statements. Each SQL
SELECT statement within the UNION query must have the same number of fields in the result sets
with similar data types.