Question

You need to write a query that returns all Employees that have a LastName starting with the letter A. Which WHERE clause should you use to fill in the blank in this query?

a) WHERE LastName LIKE 'A%'
b) WHERE LastName = 'A%'
c) WHERE LastName LIKE '%A%'
d) WHERE LastName = '%A%'

Answer 1

The correct WHERE clause to find all employees with a last name starting with 'A' is 'WHERE LastName LIKE 'A%''. The LIKE operator with '%' wildcard effectively matches any last names beginning with 'A'.

Step-by-step explanation:

The student's query requires finding all employees with a last name starting with the letter 'A'. The correct choice for the WHERE clause in SQL to achieve this would be option a) WHERE LastName LIKE 'A%'. This is because the LIKE operator is used to search for a specified pattern in a column. Here '%' acts as a wildcard character, matching any sequence of characters. Therefore, 'A%' will match any last name starting with 'A' followed by any combination of characters.

Option b) WHERE LastName = 'A%' is incorrect because the equals sign is a literal comparison operator, and will not treat '%' as a wildcard. Option c) WHERE LastName LIKE '%A%' would return last names that contain 'A' at any position, and option d) WHERE LastName = '%A%' would mistakenly attempt a literal comparison including the wildcard characters which SQL does not allow.