PostgreSQL BETWEEN Operator: A Critical 101 Guide

PostgreSQL has more than 20 years of active development and an established design, which has earned it a high reputation for dependability, data integrity, and accuracy. PostgreSQL is not only famous for its importance, but it also offers many operators for the built-in data types. An operator is a reserved word or character used primarily in the WHERE clause of a PostgreSQL statement to conduct operation(s) such as comparisons and arithmetic computations. 

When querying a database, you may wish to limit your results to a specific range of values. This article will discuss the introduction to PostgreSQL and list its key features. You will learn about the advantages of the PostgreSQL BETWEEN Operator and provide examples of using it in SQL queries.

Table of Contents

• What is PostgreSQL?
  • Key Features of PostgreSQL
• What is BETWEEN Operator in PostgreSQL?
• Why is PostgreSQL BETWEEN Operator Important?
• PostgreSQL BETWEEN Operator Syntax, Examples, and Use Cases
  • Syntax and Use Cases
  • Examples of Implementing PostgreSQL BETWEEN with Different Datatypes 
  • Use Cases 
• Conclusion

What is PostgreSQL?

PostgreSQL is a robust, enterprise-class, open-source relational database management system that queries relational data using standard SQL and non-relational data with JSON. PostgreSQL has good support for all operating systems, including Linux, UNIX, and Windows. 

This platform is suited for managing many workloads, from single computers to massive Cloud-based Data Warehouses. It enables complex data types and optimization functions, often available in commercial databases like Oracle, SQL Server, and others. PostgreSQL also carefully adheres to SQL standards.

You can refer to PostgreSQL documentation to know more.

Key Features of PostgreSQL

• Open-source: The open-source nature of PostgreSQL allows you to store a limitless amount of data with no restrictions on functionality. Furthermore, this platform imposes no distribution-based limits on your saved data. 
• Secure: PostgreSQL supports many authentication protocols, including Lightweight Directory Access Protocol (LDAP), Generic Security Service Application Program Interface (GSSAPI), Security Support Provider Interface (SSPI), and others. It also has a robust Access Control System and column and row-level security.
• Broad User base: PostgreSQL users include well-known companies like Apple, Cisco, Etsy, Facebook, Instagram, Red Hat, Skype, Spotify, and Yahoo.
• Customize functions: PostgreSQL may be changed by writing plugins to match your specific requirements. PostgreSQL also supports custom functions written in other programming languages like Java, C, C++, and others.
• ACID-compliant: Write-ahead logging in PostgreSQL makes it a fault-tolerant database. PostgreSQL is ACID-compliant and supports foreign keys, joins, views, triggers, and stored procedures in various languages. Its broad community of open source contributors provides it with a built-in support network.

What is BETWEEN Operator in PostgreSQL?

The PostgreSQL BETWEEN Operator works with SELECT, INSERT, UPDATE, or DELETE statements to get data inside a range. In other words, PostgreSQL BETWEEN Operator compares a value to a range of values. The PostgreSQL Between Operator is also known as the PostgreSQL Between condition.

Suppose you have a product database with a product details table. The table consists of product_id, product_price, and product_name columns. If you want to know what products have prices ranging between $200 to $500, BETWEEN Operator is helpful in this scenario.

Why is PostgreSQL BETWEEN Operator Important?

Operators are provided in RDBMS(Relational Database Management Systems) to simplify operations on data retrieval. These operations include Arithmetic Operations, Logical Operations, Bitwise Operations, and Comparaision Operations. The BETWEEN Operator comes under the umbrella of Comparision Operators.

As of now, you know the basic definition of BETWEEN Operator. Its importance is indulged in its description. With the help of BETWEEN Operator, you can quickly check if the expression is lying within the range provided(inclusive) or not.

PostgreSQL BETWEEN Operator Syntax, Examples, and Use Cases

Syntax and Use Cases

In PostgreSQL, the syntax for the BETWEEN condition is:

Syntax:

value BETWEEN low AND high;

Where, 

• value can be a column or computation on a table.
• low and high numbers define an inclusive range against which expression is compared.

The expression returns true if the value is larger than or equal (>=) to the low value and less than or equal (<=) to the high value; otherwise, it returns false.

You  can alternatively recreate the BETWEEN Operator using the larger than or equal (>=) or less than or equal (<=) operators, as seen in the syntax below:

Syntax:

value >= low and value <= high;

Use Cases

The PostgreSQL BETWEEN Operator compares a value to a range of values. PostgreSQL allows for numerical values and dates. You can leverage BETWEEN with NOT Operator. To retrieve values that do not fulfill the BETWEEN condition, you can combine the NOT Operator with the PostgreSQL BETWEEN Operator.

Examples of Implementing PostgreSQL BETWEEN with Different Datatypes

Let’s understand how BETWEEN Operator works with SQL Queries in PostgreSQL.

PostgreSQL BETWEEN Example with Numeric Value

Let’s look at some numeric PostgreSQL BETWEEN Operator examples. The BETWEEN condition is used in the following numeric example to extract numbers inside a numeric range.

Example:

SELECT *
FROM students
WHERE student_id BETWEEN 100 AND 200;

Alternatively above query can be written as below:

SELECT *
FROM students
WHERE student_id >= 100
AND student_id <= 200;

The above PostgreSQL BETWEEN example would return all entries from the student’s table where the student_id  is between 100 and 200(inclusive). 

PostgreSQL BETWEEN Example with Date 

Let’s now look at using the PostgreSQL BETWEEN Operator with Dates.
The BETWEEN condition is used in the following date example to get data inside a date range.

Example:

SELECT *
FROM students
WHERE batch_start_date BETWEEN '2022-04-01' AND '2022-07-30';

Alternatively above query can be written as below:

SELECT *
FROM students
WHERE batch_start_date >= '2022-04-01'
AND batch_start_date <= '2022-07-30';

The above query will return the student’s data whose batch_start_date is between 2022-04-01 and 2022-07-30.

PostgreSQL BETWEEN Example with NOT Operator

In PostgreSQL, you can use the NOT operator in conjunction with the BETWEEN Operator. It is combined with the WHERE clause to get data from a table if the stated condition contradicts the PostgreSQL between states.

Example:

SELECT student_id, student_name, student_age  FROM students WHERE student_age NOT BETWEEN 23 AND 26;

Alternatively above query can be written as below:

SELECT student_id, student_name, student_age  FROM students WHERE student_age >= 23 OR student_age<= 26;

The above query will return the student’s data whose age is not between the range of 23 and 26.

Conclusion

In this blog post, you have learned about PostgreSQL BETWEEN Operator as well as its importance. You also walk through different syntax and examples provided for different scenarios to better under the subject. 

PostgreSQL is quite a famous RDBMS. Its user base and use cases are increasing day by day. Having a clear understanding of its features and operators helps developers. There are many other operators in PostgreSQL such as Arithmetic Operators, Bitwise Operators, and Logical Operators. You can discover about them as well.

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