POSTGRESQL DATABASE INTERVIEW QUESTIONS

What is a NULL value in PostgreSQL and how is it different from an empty string or zero?

How do you define a column to be NOT NULL in PostgreSQL?

What happens if you try to insert a NULL value into a column defined as NOT NULL in PostgreSQL?

Can a unique constraint be applied to a column with NULL values in PostgreSQL? Explain.

How does PostgreSQL handle NULL values in comparisons?

What is the default behavior for columns regarding NULL values in PostgreSQL if no constraint is specified?

Explain the concept of a NULL constraint in PostgreSQL and its practical use cases.

How does PostgreSQL treat NULL values in aggregate functions like COUNT, SUM, and AVG?

Discuss the implications of using NULL values in PostgreSQL when creating indexes.

What are the best practices for handling NULL values in PostgreSQL to maintain data integrity and optimize query performance?