Which of the following statements are true about group functions?
Each correct answer represents a complete solution. Choose all that apply.
A.
Group functions return a single result based on a number of rows as opposed to the single row
functions.
B.
Different group functions are AVG, COUNT, MAX, MIN, STDDEV, SUM, and VARIANCE.
C.
All group functions except the COUNT (*) and GROUPING functions ignore NULL values.
D.
The NVL function forces group functions to include duplicate values.