What is the minimum number of WHERE clauses that must be present in a SELECT query?

In SQL, the minimum number of WHERE clauses that must be present in a SELECT query is zero. The WHERE clause is optional. This means you can write a SELECT statement without including a WHERE clause to retrieve all records from the specified table.

For example, a simple SELECT query without a WHERE clause looks like this:

SELECT * FROM Employees;

This query retrieves all records from the Employees table. However, if you want to filter the results based on certain conditions, you would add one or more WHERE clauses. A WHERE clause allows you to specify criteria for selecting rows from the table, such as:

SELECT * FROM Employees WHERE department = 'Sales';

In this case, only the records of employees who work in the Sales department will be returned. Thus, while you can have multiple WHERE clauses (using AND/OR for complex conditions), it is not necessary to include any WHERE clause at all.