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Education

This is the Education section of the Command Prompt Website. Here you will find blogs specifically about how to use Postgres and related technologies.

PostgreSQL Else If Statement With Examples

In Postgres, the ELSIF is one of the decision-driven statements that evaluate several conditions. It checks/evaluates each condition one by one.

PostgreSQL TRUNCATE VS DROP VS DELETE

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.

PostgreSQL If Else Statement With Examples

In Postgres, the if statement checks a condition/criteria and returns true or false. If statement doesn’t handle the false condition. To handle the false conditions, the else statement is used in PostgreSQL.

PostgreSQL Upsert Using INSERT ON CONFLICT Statement

In PostgreSQL, the upsert feature is used either to update existing records or insert new ones into a table. The upsert feature is implemented using the INSERT ON CONFLICT statement.

PostgreSQL Copy Table With Practical Examples

PostgreSQL allows us to copy an existing table with or without data. In Postgres, either you can copy only the structure of an existing table, or you can copy a table completely along with its data.

PostgreSQL Create Table IF NOT EXISTS

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.

PostgreSQL SUBSTRING() Function - How to Extract a Substring From a String

PostgreSQL provides a built-in function named SUBSTRING() that extracts a substring from any specific string. The SUBSTRING() function accepts three parameters: a string, starting position, and length. The starting position” and “length” parameters are optional that can be skipped depending on the situation.

This write-up will present a detailed overview of extracting a substring from a string using the PostgreSQL SUBSTRING() function. So, let's get started.

How to Use SUBSTRING() …

Connecting PostgreSQL Using psql and pgAdmin

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 …

PostgreSQL AGE() Function With Examples

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

PostgreSQL TO_DATE() Function: Convert String to Date

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.