1. What is the purpose of the "DISTINCT" keyword in a SELECT statement?
2. What is the default data type for a PostgreSQL serial column?
3. Which SQL clause is used to join tables based on a common column?
4. What is the purpose of the "NULL" value in a PostgreSQL database?
5. What is the purpose of the PostgreSQL "pg_dump" utility?
6. In PostgreSQL, what is the difference between the "INNER JOIN" and "LEFT JOIN" clauses?
7. What is the purpose of the PostgreSQL "pgAdmin" tool?
8. Which PostgreSQL data type is used to store date and time values?
9. What is the purpose of the PostgreSQL "VACUUM" command?
10. Which SQL statement is used to remove a table from a PostgreSQL database?
11. What is the purpose of the "COALESCE" function in PostgreSQL?
12. What does the term "transaction" refer to in a PostgreSQL database?
13. What is the purpose of the "CASE" statement in SQL?
14. In PostgreSQL, what is a "composite key"?
15. What is the purpose of the "ENUM" data type in PostgreSQL?