DA SQL and Database Querying

Question 1

Which SQL clause is used to filter rows after a GROUP BY operation?

Accepted Answer

HAVING

Answer

WHERE

Answer

ORDER BY

Answer

FILTER

Question 2

What does a LEFT JOIN return?

Accepted Answer

All rows from the left table and matching rows from the right

Answer

Only matching rows from both tables

Answer

Only rows unique to the left table

Answer

All rows from both tables with no filtering

Question 3

Which aggregate function counts only non-NULL values in a column?

Accepted Answer

COUNT(column_name)

Answer

COUNT(*)

Answer

SUM()

Answer

AVG()

Question 4

What is the purpose of the SQL DISTINCT keyword?

Accepted Answer

Remove duplicate rows from the result set

Answer

Sort results in ascending order

Answer

Filter rows based on a condition

Answer

Join two tables together

Question 5

Which SQL statement is used to modify existing data in a table?

Accepted Answer

UPDATE

Answer

INSERT

Answer

ALTER

Answer

MODIFY

Question 6

What does the SQL ORDER BY clause do?

Accepted Answer

Sorts result rows by one or more columns

Answer

Groups rows by a column value

Answer

Filters rows meeting a condition

Answer

Removes duplicate values