Postgres and Open Source Experts

In Postgres, creating a table that already exists will result in an error stating that the "relation already exists". To avoid such errors, the IF NOT EXISTS clause is used with the CREATE TABLE command.

This blog post explained date data types, functions, operators, formats, and intervals with the help of appropriate examples.

To check which PostgreSQL version is active on your system, users can run “psql –version” command from the command prompt, or the “SELECT VERSION()” command from SQL Shell.

To kill a process in Postgres, first, find the “pid” for all the processes, and then run the “pg_cancel_backend(pid)” and “pg_terminate_backend(pid)” commands.

PostgreSQL provides various sequence functions like SETVAL(), NEXTVAL(), CURRVAL(), and LASTVAL() to work with sequences efficiently.

To find the list of users, databases, schemas, or tables, the meta-commands like “\du”, “\l”, “\dn”, and “\dt” are used, respectively.

psql is a command-line interface used to perform various database tasks efficiently. For instance, using psql different commands can be executed to access, create, delete, or update a database, table, schema, etc.

In Postgres, the TRUNCATE TABLE command only removes the table’s data and preserves the table’s structure. While the DROP TABLE command drops the table’s data and structure permanently.

regexp_matches() function takes in the string and the regular expression to be matched as an argument along with an optional flag and returns the first matched substring from the main string.

Use the “sudo apt install postgresql postgresql-contrib” command to install PostgreSQL from Debian 12’s default repository.