Postgres and Open Source Experts

PostgreSQL provides a Date function named CURRENT_DATE, which retrieves the current/today’s date. It retrieves the date in “YYYY-MM-DD” format.

PostgreSQL provides a built-in DateTime function named CURRENT_TIME that retrieves the current time with time zone offset.

In Postgres, a built-in function named “LOCALTIMESTAMP” is used to get today’s Date and Time without timezone information.

The STRING_AGG() function in Postgres is used to concatenate multiple strings into a single string, separated by a specific delimiter/separator.

In Postgres, the CREATE VIEW statement defines a new view based on the selected table(s). To create a view from several tables, use the CREATE VIEW statement with INNER JOIN.

In PostgreSQL, the “\d”, “\dv”, “\dv+” commands, “information_schema.views”, etc., are used to list all the views from a database.

In Postgres, the ALTER VIEW command modifies the views’ definition, such as setting the column's default value, changing the view’s owner, renaming a view, etc.

Postgres provides a “CREATE OR REPLACE VIEW” statement to create a new view or replace an existing view's defining query. It allows us to modify the defining query of a view without dropping a view. It defines a new view if the desired view doesn’t exist already or modifies the view’s defining query if it already exists.

This blog explains how to replace the view’s definition using the “CREATE or …

In PostgreSQL, the “\d” command, “\d+” command, “information_schema”, and “pgAdmin” are used to list all columns of a table.

“\List”, “\l”, and “pg_database” is used in SQL Shell to get the database list. While to switch databases in SQL Shell, the “\c” and “\connect” commands are used.