A Level Computer Science OCR Practice Exam

What is required in the SQL WHERE clause?

1. A numerical value for filtering

2. A boolean statement as search criteria

3. The name of the column to be updated

4. An aggregate function

The correct answer is: A boolean statement as search criteria

The correct answer is that the SQL WHERE clause requires a boolean statement as search criteria. The WHERE clause is essential in SQL for filtering records based on specific conditions. It allows the user to specify criteria that the rows must meet to be included in the result set. A boolean statement evaluates to true or false and typically involves comparisons between columns and values, such as equality, inequality, or other relational operations. In this context, filtering rows based on conditions can include expressions like `column_name = value`, `column_name > value`, or combinations using logical operators like AND and OR, all resulting in boolean evaluations that determine whether a row meets the criteria for selection. While numerical values can be part of these comparisons, they do not constitute the requirement of the WHERE clause by themselves. Similarly, the name of a column for updating is associated with the SET clause during an UPDATE operation, and aggregate functions are used in grouping or summarizing data rather than in filtering it directly.