Postgres and Open Source Experts

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.

The DROP command throws an error if a table to be dropped doesn’t exist while “DROP IF EXISTS” shows a notice instead of throwing an error.

In Postgres, the SELECT DISTINCT clause fetches only unique values from a result set returned by a query. It retains only one row from a set of duplicated rows.

In PostgreSQL, the COALESCE() function handles the null values more efficiently. It accepts unlimited arguments and returns the first non-null argument.

PostgreSQL doesn’t provide a DATEADD function to add an interval to date time. However, you can achieve the same functionality using the “+” and “-” operators.

PostgreSQL provides various functions, such as LOWER(), INITCAP(), or UPPER(), to alter a string to lowercase, proper case, and uppercase, respectively.

PostgreSQL offers multiple date/time functions, such as CURRENT_DATE, NOW(), EXTRACT(), CURRENT_TIMESTAMP, etc. If we talk about the CURRENT_TIMESTAMP function, it retrieves the current date, time, and timezone when a transaction starts.

This write-up will present a thorough overview of the Postgres CURRENT_TIMESTAMP function with examples. So, let’s begin.

How to Use CURRENT_TIMESTAMP Function in PostgreSQL?

Firstly, let’s understand the syntax of the CURRENT_TIMESTAMP function:

CURRENT_TIMESTAMP(<precision>);

Here, “precision” is an optional …