Question

Which aggregate function in SQL displays the number of values in the specified column ignoring the NULL values?

• A. len()
• B. count()
• C. number()
• D. num()

Hint:

Use COUNT(*) to count all rows including NULLs,
and COUNT(column_name) to count only non-NULL entries.

Answer 1

The Correct Option is B

In SQL, the COUNT() function is an aggregate function
used to count the number of rows that match a specified condition.
When used on a column, COUNT() counts only the non-NULL values.
It ignores any NULL entries in that column automatically.
len(), number(), and num() are not valid SQL aggregate functions.
len() exists in Python but not in SQL.
Therefore, the function that counts values ignoring NULLs is COUNT().
So, option (B) is correct.