Which of the following group functions ignore NULL values?
A. MAX
B. COUNT
C. SUM
D. All of the above
Answer: Option D
Solution (By Examveda Team)
All three of the listed SQL group functions,MAX, COUNT, and SUM, have the ability to ignore NULL values when processing data within their respective functions. Here's a brief explanation of each option:Option A:
MAXThe
MAX function is used to find the maximum (largest) value in a set of values. It can operate on a column and will return the maximum value, ignoring NULL values in that column.Option B:
COUNTThe
COUNT function is used to count the number of rows in a result-set or the number of non-NULL values in a specific column. It ignores NULL values when counting.Option C:
SUMThe
SUM function is used to calculate the sum of all values in a numeric column. It adds up all the non-NULL values and produces a result, ignoring NULL values.Option D:
All of the aboveThis option is correct because all of the mentioned group functions (
MAX, COUNT, and SUM) have the capability to ignore NULL values when performing their respective operations.So, the correct answer is
Option D: All of the above. This Question Belongs to SQL >> Sql Miscellaneous
Answer D
Reason:
1. MAX: Will check for the possible numeric value in the database. Hence Ignore NULL.
2. Count : select Count(name) from xyz, this will Return 0 if Found NULL in name of all records {NULL is getting ignore},
whereas count(1) will return number of rows.
3.SUM: SUM is basically used to add Amount Type Fields in DB. 0 + NULL Will create NULL.
why group functions ignore null values
All aggregate functions above ignore NULL values except for the COUNT function.