In SQL, which operator is specifically used to compare two values for inequality in a WHERE clause?

Introduction / Context:
Comparison operators are a core part of SQL, because they determine how rows are filtered in WHERE clauses and JOIN conditions. Many operators exist, such as equality, inequality, less than, and greater than. This question focuses on the operator that checks whether two values are not equal to each other, which is a very common need when writing conditions in queries.

Given Data / Assumptions:

• We are using standard SQL comparison operators.
• The question asks specifically for the operator that tests inequality.
• The operator will be used in a WHERE clause or a join condition.

Concept / Approach:
In standard SQL, the operator for inequality can be written as <> in many database systems, and some systems also support != as an alternative. The symbol = is used for equality, not inequality. Characters such as the backtick and slash are not comparison operators in SQL; they have other meanings or are not used at all in the SQL language. Therefore, the main task is to identify the operator among the options that correctly represents not equal to in SQL.

Step-by-Step Solution:
Step 1: Recall that = is used in SQL for equality, as in column = 10, so it is not the inequality operator. Step 2: Recall that in many SQL dialects, not equal to is written as <>, for example column <> 10. Step 3: Recognize that the backtick character is not a comparison operator; in some systems it may delimit identifiers but it does not compare values. Step 4: Recognize that the slash character is typically used for division or special syntax, not for comparing values. Step 5: Conclude that the operator <> is the correct SQL operator to test for inequality between two values.

Verification / Alternative check:
To verify, consider a query such as SELECT * FROM products WHERE price <> 100. This retrieves all products whose price is not equal to 100. Running the equivalent with = would retrieve only those equal to 100. Most SQL tutorials and documentation use <> to represent inequality, confirming that this is the intended comparison operator.

Why Other Options Are Wrong:
Option A is incorrect because = is an equality operator and checks whether two values are the same, not whether they are different. Option C is incorrect because the backtick symbol is not a comparison operator; in some databases it is used around identifiers but not in logical comparisons. Option D is incorrect because the forward slash is associated with division or special syntax and is not a standard operator for comparing values in SQL.

Common Pitfalls:
A common mistake is to assume that != is always the portable inequality operator in SQL. While many database systems support !=, the standard portable form is <>. Developers coming from other programming languages sometimes forget this and use only !=, which may not work in all SQL dialects. Another pitfall is confusing comparison operators with logical operators like AND or OR, which combine conditions rather than compare values directly.

Final Answer:
The operator used in SQL to compare two values for inequality is <>, which corresponds to option B.