POSTGRESQL DATABASE INTERVIEW QUESTIONS

What is the purpose of the WHERE clause in PostgreSQL?

How do you use the WHERE clause to find records in a table that meet multiple conditions?

What happens if you don't use a WHERE clause in a SELECT statement?

Can you use the WHERE clause with aggregate functions like SUM or COUNT in PostgreSQL? Provide an example.

Explain the difference between WHERE and HAVING clauses in PostgreSQL.

How would you use a subquery with the WHERE clause in PostgreSQL? Provide an example.

Describe how to use the WHERE clause with the EXISTS keyword in PostgreSQL.

How can you optimize a query with a complex WHERE clause in PostgreSQL?

What is the difference between using WHERE and JOIN ON conditions in PostgreSQL? When should you prefer one over the other?

Explain how the WHERE clause can be used in conjunction with window functions in PostgreSQL. Provide an example.