Amazon Athena
User Guide

When to Use Views?

You may want to create views to:

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

  • Combine multiple tables in 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 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.

  • Experiment with optimization techniques and 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 the underlying table and column names, and minimize maintenance problems if those names change. In that case, you recreate the view using the new names. All queries that use the view rather than the underlying tables keep running with no changes.