SQL code copied to buffer

Task

Using a covering index

The actor table has an index idx_actor_last_name on the last_name column. Which of the following queries can use this index as covering index?

select last_name, count(*) from actor group by last_name;

select last_name, last_update from actor order by last_name desc;

select last_name from actor order by last_update;

select distinct last_name from actor;

Mark all correct answers and click the "Check!" button

Get hint

Support SQLtest.online

This project has only one funding source: your donations. The monthly maintenance cost is $100.

Last month I added a new MariaDB database with a preloaded University DB, 9 new questions, and refactored many questions and lessons.

With your support, I plan to continue this work: write new lessons and tasks, and improve existing lessons.

To keep the project running next month, we need to collect at least this amount by the end of this month. Anything above it goes to new lessons, exercises, and features.

Received: $3.73 Goal: $100.00

Progress: 4%

SQL Essentials for Data Analysis: A 50-Day Hands-on Challenge Book by Benjamin Bennett Alexander

SQL Essentials for Data Analysis: A 50-Day Hands-on Challenge Book by Benjamin Bennett Alexander

If you’re wondering whether you should learn SQL, the answer is simple: absolutely. SQL (Structured Query Language) is the language of data, and data powers every modern business. Whether you’re a data analyst, data scientist, business analyst, software engineer, financial analyst, product manager, or marketing professional, SQL helps you retrieve, analyze, and understand the information that drives decisions.

Hi! Could we please enable some services and cookies to improve your experience and our website?

Privacy & Cookie Policy.