In SQL, which operator is commonly used in a WHERE clause to perform pattern matching on character data?

Introduction / Context:
Pattern matching on strings is a frequent requirement in database queries. For example, you might want all customers whose names start with a certain letter or all products that contain a specific word in their description. SQL provides operators to support such pattern based searches. This question asks you to identify the standard operator used in WHERE clauses for simple pattern matching on character data.

Given Data / Assumptions:

• The database language considered is SQL.
• We are working with character or text columns.
• The goal is to match patterns such as starting with or containing a substring.

Concept / Approach:
The LIKE operator in SQL allows you to specify patterns using wildcard characters such as percent and underscore. For example, name LIKE 'A%' matches any value starting with A, and name LIKE '%son' matches any value ending with son. EXISTS and BETWEEN operators have different purposes: EXISTS checks for the existence of rows in a subquery and BETWEEN checks whether a value lies in a range. Therefore, LIKE is the correct choice for pattern matching.

Step-by-Step Solution:
Step 1: Recall that pattern matching typically uses wildcard characters like percent and underscore.Step 2: Remember that in SQL, these wildcards are used with the LIKE operator in WHERE conditions.Step 3: Option A explicitly names the LIKE operator.Step 4: Option B, EXISTS, is used to test whether a subquery returns at least one row and is not for pattern matching.Step 5: Option C, BETWEEN, checks if a value lies between two given values, which is different from string patterns, while option D is incorrect because a suitable operator does exist.

Verification / Alternative check:
Examples from any SQL tutorial show statements such as SELECT * FROM employees WHERE first_name LIKE 'J%'; to find employees whose first name starts with J. There is no way to perform this simple pattern based filtering with BETWEEN or EXISTS. This practical usage confirms that LIKE is the required operator for basic pattern matching on text values.

Why Other Options Are Wrong:
Option B, EXISTS, evaluates to true if the subquery returns any rows and is commonly used for correlated subqueries. Option C, BETWEEN, is generally applied to numeric or date fields to check ranges and not for substring matching. Option D is wrong simply because the LIKE operator is available for this purpose.

Common Pitfalls:
Beginners sometimes confuse LIKE with equality or try to use range conditions for partial text matching. Another pitfall is forgetting that LIKE with wildcards can be slower on large tables if indexes are not used properly. However, for exam purposes, it is enough to remember that LIKE is the keyword for simple pattern matching in SQL WHERE clauses.

Final Answer:
LIKE operator