Create view psql how to#

A view that joins a large number of database tables that is used for a wide variety of queries.

Create view psql how to#

The query's execution plan tends to be complicated and it is difficult to understand and how to improve it.ĭefining a denormalized 'world' view. Problems arise when you try to enhance or troubleshoot queries that use the views, for example by examining the execution plan. SELECT CONCAT ( 'CREATE MATERIALIZED VIEW IF NOT EXISTS '', tablename, 'factor', i, '' AS SELECT id, POWER (2,', i,') AS factor ', 'FROM '', tablename, '' WHERE factor IS NOT NULL ' ) FROM informationschema.tables WHERE tablename LIKE 'prefix' AND tablename NOT LIKE 'suffix' AND tableschema not in ('informationschema', 'pgc. These are two patterns of creating views that tend to be problematic because the view's SQL is used during query execution.ĭefining many layers of views so that your final queries look deceptively simple. Postgres extension called mvstats, which allows the DataOps to track and query this information in a more practical manner. In general, these uses do not require nesting views, that is, defining views based on other views. The following SQL creates a view that selects all. If a subquery is associated with a single query, consider using the WITH clause of the SELECT command instead of creating a seldom-used view. A view is a virtual table based on the result set of an SQL statement.

They can be used as an interface to abstract from the actual table definitions, so that you can reorganize the tables without having to modify the interface.

They allow you to have a recurring SQL query or expression in one place for easy reuse.

When defining and using a view, remember that a view is just an SQL statement and is replaced by its definition when the query is executed.