SQL Views: When They Help and When They Hurt
Views can simplify access and encapsulate logic, but they can also hide expensive queries. Here is how I decide to use them. Views are saved queries that you can query like tables. They encapsulate complex logic, simplify access for users who should not see the underlying schema, and provide a stable interface when the underlying tables change. I have used views to good effect, and I have also seen them create performance problems that took days to diagnose. Here is how I decide when to create a view and when to leave the query inline. Creating a Basic View The CREATE VIEW statement saves a query under a name. You then query the view as if it were a table, and the database expands it into the underlying query at run time. CREATE VIEW active_customers AS SELECT id, name, email, created_at FROM customers WHERE status = 'active' AND deleted_at IS NULL; SELECT * FROM active_customers WHERE created_at >= '2026-01-01'; This view presents only active, non-deleted customers. Any query against the view automatically applies the filter, so users and applications do not need to remember the conditions. The view becomes the interface, and…