View

A View is a virtual table that does not store data, essentially a saved SQL query. Each time a view is queried, the system executes the underlying SQL in real time and returns the results.

Type Selection Reference

When to use a view: Encapsulating complex JOIN logic, exposing only certain columns externally (permission isolation), and scenarios where data storage is not needed.

Typical Use Cases

• Simplify queries: Encapsulate multi-table JOINs as views so business users can query the view directly
• Permission isolation: Expose only certain columns to specific users, hiding sensitive fields
• Logic reuse: Define common calculation logic once and reference it in multiple places

Quick Example

-- Create a view: hide sensitive fields
CREATE VIEW v_user_public AS
SELECT user_id, username, city
FROM users;
-- Do not expose sensitive columns like phone, id_card

-- Create a view: encapsulate complex JOINs
CREATE VIEW v_order_detail AS
SELECT o.order_id, u.username, p.product_name, o.amount
FROM orders o
JOIN users u ON o.user_id = u.user_id
JOIN products p ON o.product_id = p.product_id;

Related Documentation

• CREATE VIEW — Full syntax
• Materialized View — When you need to store pre-computed results
• Semantic View — Semantic layer for business analysis