SQL Aggregate Functions and Grouping 2

Question 1

Which aggregate function returns the total number of rows, including those with NULL values in the counted column?

Accepted Answer

COUNT(*)

Answer

COUNT(column)

Answer

COUNT(DISTINCT column)

Answer

SUM(column)

Question 2

What does AVG(salary) ignore when computing the average?

Accepted Answer

NULL values

Answer

Zero values

Answer

Negative values

Answer

Duplicate values

Question 3

In a query with GROUP BY department, which column can appear in SELECT without being aggregated?

Accepted Answer

department

Answer

salary

Answer

hire_date

Answer

employee_id

Question 4

Which clause filters groups based on an aggregate condition like SUM(amount) > 1000?

Accepted Answer

HAVING

Answer

WHERE

Answer

ON

Answer

FILTER

Question 5

What is the result of COUNT(DISTINCT city) on a column with values 'NY','NY','LA',NULL?

Accepted Answer

2

Answer

1

Answer

3

Answer

4

Question 6

Which function returns the largest value in a numeric column?

Accepted Answer

MAX

Answer

TOP

Answer

GREATEST

Answer

HIGH

Question 7

In the logical order of execution, when is GROUP BY processed relative to WHERE?

Accepted Answer

After WHERE

Answer

Before WHERE

Answer

Same time as WHERE

Answer

After SELECT