POSTGRESQL DATABASE INTERVIEW QUESTIONS

What does the DISTINCT keyword do in PostgreSQL?

Can you use DISTINCT with multiple columns in PostgreSQL?

Is it possible to use DISTINCT with aggregate functions in PostgreSQL?

Explain how DISTINCT ON works in PostgreSQL and provide a use case.

What is the difference between DISTINCT and DISTINCT ON in PostgreSQL?

How does the performance of DISTINCT queries compare to using GROUP BY in PostgreSQL?

How can you optimize queries that use DISTINCT in PostgreSQL for large datasets?

Can DISTINCT be used with window functions in PostgreSQL, and if so, how?

What are the implications of using DISTINCT in a subquery versus using it in the main query in PostgreSQL?

In a PostgreSQL certification exam, you might be asked: What are the potential performance impacts of using the DISTINCT keyword in large ORACLE datasets, and how can these impacts be mitigated?