Writing simpler multi-condition filters in SQL When three or more AND and OR conditions are being combined to test membership or non-membership in a list of values, which SQL keyword(s) make the expression clearer and easier to maintain?

Introduction / Context:
As SQL predicates become longer, readability and correctness suffer. A classic case is when you need to check whether a column's value belongs to several alternatives, or explicitly does not belong to them. Instead of chaining many OR or AND comparisons, SQL provides concise list-membership operators that make intent obvious and reduce mistakes.

Given Data / Assumptions:

• You are filtering rows based on whether a column equals one of several values, or must avoid a set of values.
• Three or more comparisons are present; maintainability matters.
• The value list is finite and known in the statement or parameterized.

Concept / Approach:

Use IN to replace a chain of OR equality tests, and use NOT IN to replace a chain of AND inequality tests. These operators express set membership and non-membership directly, improving clarity and aiding optimizers in some systems. They are ideal when comparing a single expression against a list of constants or a subquery result set.

Step-by-Step Solution:

Verification / Alternative check:

Most vendor style guides recommend IN/NOT IN for readability and correctness when evaluating membership, and many show measurable simplification in code reviews and query linting tools.

Why Other Options Are Wrong:

• LIKE only: pattern matching, not set membership.
• IN only or NOT IN only: both are needed for membership and non-membership cases.
• BETWEEN only: tests a continuous range, not a discrete list.

Common Pitfalls:

• Using NOT IN with a subquery that can return NULL; rows will be filtered out unexpectedly. Prefer NOT EXISTS in that case.
• Forgetting to parameterize long lists that repeat across queries.

Final Answer:

Both IN and NOT IN.