Before attempting a database question on HackerRank, ensure that your environment is set up correctly. If you are new to the platform, take the sample test provided in your invitation email to become familiar with the interface.

Supported database languages

HackerRank supports the following database management systems:

• Microsoft SQL Server

• MySQL

• PostgreSQL

• DB2

• Oracle

You can select from the available options at the top of the editor. All queries run on standard database servers hosted in an Ubuntu environment.

Solving a database question

To solve a database question:

1. Select a database question from the test dashboard and click Solve.

2. Review the problem statement and any associated schema in the left panel.

   

3. Select a supported database language from the dropdown in the coding interface.

   

4. Write your SQL query in the code editor.

5. Click Run to execute the query and validate your solution. The results panel displays pass or fail status and any error messages, if applicable.

   

6. Click Submit when you are ready to finalize your solution.

Guidelines for writing and formatting queries

Database questions include one or more tables, along with schema details in the problem description. Your task is to write SQL queries that return the expected output.

• Exact output format: Scoring is based on exact string matching. Your output must match the expected result precisely.

• Ordering: If no specific output order is mentioned, the result may appear in any sequence.

• Precision: Ensure numerical formats match exactly. For example, 9.0 is not equal to 9.

• Spelling and case sensitivity: Output must exactly match the format described in the prompt, including spelling and case.