Experts in Postgres and Open Source Infrastructure

24x7, 365 Enterprise services since 1997

Education

Professional Postgres and Open Source support

Command Prompt, Inc., is the oldest Postgres Company in North America and one of the oldest Open Source firms still operating today. We serve our clients with best in class expertise and professionalism. You can read more about support and services here:


You have landed at the largest single source of Postgres education blogs in the world. At Command Prompt, we believe deeply that the education of the community is critical to the continued success of Postgres and related technologies. We hope you find content you are looking for and don't hesitate to Contact us today for all your Postgres and Open Source consulting and support needs.

How to Use MAX() Function in PostgreSQL

PostgreSQL offers a built-in MAX() function that is used to retrieve the maximum value of a set. The MAX() function has multiple real-life implementations, such as fetching the highest-paid employee, finding a top-ranked student, and so on. So, let’s learn the working of the MAX() function through Practical examples.

How to Use MAX() Function in Postgres?

The below snippet will show you the basic syntax of the MAX() function:

MAX(exp); …

How to Use AVG() Function in PostgreSQL

In PostgreSQL, the AVG() function is used to retrieve the average of a set. The DISTINCT operator is used with the AVG() function to find the average of distinct values.

PostgreSQL SUM() Function With Practical Examples

The SUM() is used to perform the addition on a set of values. Use the DISTINCT option with the SUM() function to calculate the sum of distinct values.

How to Use COUNT() Function in PostgreSQL

The table rows can be counted using PostgreSQL's COUNT() function. It is an aggregate function that enables us to count the rows that meet the specified condition. There are multiple ways to use the COUNT() function, such as COUNT(*), COUNT(col_name), and COUNT(DISTINCT col_name). Each implementation of the COUNT() function serves a different functionality.

Let’s learn the working of the COUNT() function through Practical examples.

How to Use COUNT(*) Function in …

How to Use the POSITION() Function in PostgreSQL

In PostgreSQL, to get the substring’s location in a string, the POSITION() function is used. It returns an integer that represents the substring’s location.

How to Use NOT IN Operator in PostgreSQL

In PostgreSQL, the NOT IN operator filters the query results and returns all the values of a result set except the specified values.

How to Get Top N Rows in PostgreSQL

To get the top n rows of a table, the LIMIT clause is used in PostgreSQL. It assists us in getting the subset of rows generated by a query.

PostgreSQL SMALLINT Data Type With Examples

In PostgreSQL, the SMALLINT is used to store small integer values. It takes 2 bytes of storage and can store integers between -32,768 to +32,768.

PostgreSQL VARCHAR Data Type With Examples

VARCHAR(n) or CHARACTER VARYING(n) is a data type in PostgreSQL that stores textual data within a limited range. It can store n number of characters.

How to Show Tables in PostgreSQL?

Execute the “\dt” command from psql tool or use the pg_catalog schema with the aid of the SELECT query from the pgAdmin to show tables of the selected database.