Work with views

Query a subset of data – For example, you can create a view with a subset of columns from the original table to simplify querying data.

Combine tables – You can use views to combine multiple tables into one query. When you have multiple tables and want to combine them with UNION ALL, you can create a view with that expression to simplify queries against the combined tables.

Hide complexity – Use views to hide the complexity of existing base queries and simplify queries run by users. Base queries often include joins between tables, expressions in the column list, and other SQL syntax that make it difficult to understand and debug them. You might create a view that hides the complexity and simplifies queries.

Optimize queries – You can use views to experiment with optimization techniques to create optimized queries. For example, if you find a combination of WHERE conditions, JOIN order, or other expressions that demonstrate the best performance, you can create a view with these clauses and expressions. Applications can then make relatively simple queries against this view. If you later find a better way to optimize the original query, when you recreate the view, all the applications immediately take advantage of the optimized base query.

Hide underlying names – You can use views to hide underlying table and column names, and minimize maintenance problems if the names change. If the names change, you can simply recreate the view using the new names. Queries that use the view rather than the tables directly keep running with no changes.

For more information, see Work with Athena views.

Greater access control – You create a view that restricts data access based on the level of permissions the user requires. For example, you can use Data Catalog views to prevent employees who don't work in the human resources (HR) department from seeing personally identifiable information.

Ensure complete records – By applying certain filters onto your Data Catalog view, you make sure that the data records in a Data Catalog view are always complete.

Enhanced security – In Data Catalog views, the query definition that creates the view must be intact in order for the view to be created. This makes Data Catalog views less susceptible to SQL commands from malicious actors.

Prevent access to underlying tables – Definer semantics allow users to access a view without making the underlying table available to them. Only the user who defines the view requires access to the tables.