SQL views: for what purposes can views be used (rows/columns security and complexity hiding)?

Introduction / Context:
Views are powerful for security and abstraction. They can filter rows, project specific columns, and encapsulate complex joins and calculations behind a simple name.

Given Data / Assumptions:

• A view can contain a WHERE clause (row filtering).
• A view can select a subset of columns (column filtering).
• A view can wrap complex SELECTs so consumers use simple SELECT * FROM view.

Concept / Approach:
Because a view is defined by an arbitrary SELECT, it can include or exclude columns, include conditions to restrict rows, and combine multiple tables. Thus, all three use cases apply.

Step-by-Step Solution:

Verification / Alternative check:
Create sample views: one selecting limited columns, one with WHERE department_id = 10, and one wrapping a complex join. All are valid and useful.

Why Other Options Are Wrong:
Each individual option is too narrow; views support more than a single purpose.

Common Pitfalls:
Relying on views alone for security: combine with proper privileges and, when needed, row-level security policies for robust protection.

Final Answer:
All of the above are uses for SQL views