Postgres and Open Source Experts

Installing the PostgreSQL on your machine will also install a couple of very handy tools, such as pgAdmin, and SQL SHELL. pgAdmin is a web-based GUI tool, while psql is a terminal-based tool. Both these tools assist us in working with Postgres.

This write-up will assist the beginners who have installed PostgreSQL on their PCs and are now looking to establish a connection to it. This post will cover the …

The AGE() function takes two timestamps as arguments, subtracts the second timestamp from the first one, and retrieves the resultant interval.

PostgreSQL provides a built-in function named TO_DATE() that assists us in converting a string into a date. The TO_DATE() function retrieves a date value in “YYYY-MM-DD” format.

In Postgres, the CURRENT_TIMESTAMP retrieves the date and time along with the time zone, while the LOCALTIMESTAMP function retrieves the date and time without the time zone.

In PostgreSQL, the TO_TIMESTAMP() is a built-in function that accepts a string and a format and converts the given string to a TIMESTAMP based on the specified format.

In PostgreSQL, the INTERSECT operator combines the result set of at least two queries. The INTERSECT operator retrieves only common records from the targeted tables.

In PostgreSQL, there are multiple ways to export a table into a CSV file, such as the COPY statement or the \COPY command.

PostgreSQL provides a built-in function named UNNEST() that accepts an array as an argument and expands the given array into a set of rows.

Sometimes we have to store the unique records in a table, such as an email address, employee id, etc. To achieve this purpose, the “UNIQUE” constraint is used in PostgreSQL. The UNIQUE constraint allows us to store the unique rows/records in a table.

This post will explain the working of the UNIQUE constraint through practical examples. So, let’s begin.

How Does UNIQUE Constraint Work in PostgreSQL?

Each time when you …

PostgreSQL offers a CAST operator that takes an expression and a data type and converts the given expression into the specified data type.