Question: 1. In a SELECT query, what is the difference between a WHERE clause and a HAVING clause?
2. Explain why the following command would create an error and what changes could be made to fix the error: SELECT V_CODE, SUM(P_QOH) FROM PRODUCT;
3. What type of integrity is enforced when a primary key is declared?
4. Explain why it might be more appropriate to declare an attribute that contains only digits as a character data type instead of a numeric data type.