SQL Server Reverse String

In the realm of databases, manipulating, querying, and transforming data is fundamental. SQL Server provides us with a plethora of functions to help in these tasks.

Among them is the REVERSE function – a simple yet useful function that allows us to reverse the characters of a string.

In this tutorial, we will learn about how we can use the reverse function to reverse string, detecting parindromes, and more.

SQL Server Reverse Function

The REVERSE function, as the name suggests, returns the reverse of a string value. For instance, if your input is DATABASE, the function will return ESABATAD.

Function Syntax

The following shows the syntax of the reverse() function in SQL Server

REVERSE(input_string)

• input_string - The string value we want to reverse.

Examples

Example 1 - Basic Usage

Let us start with a basic example

SELECT REVERSE('DATABASE') AS Result;

Output:

Result
--------------
ESABATAD

Example 2 - Reversing Data from a Table

Suppose we have a table named Users with a column FirstName:

To reverse the FirstName of each user, we can run a query as:

SELECT UserID, FirstName, REVERSE(FirstName) AS Results
FROM Users;

The resulting table is as shown:

Example 3 - Detecting Palindromic Words:

A palindrome is a word, phrase, number, or other sequences of characters that reads the same forward and backward (ignoring spaces, punctuation, and capitalization). Using the REVERSE function, we can easily identify palindromic words:

SELECT Word 
FROM table
WHERE Word = REVERSE(Word);

Example 4 - Reversing Numbers:

While the REVERSE function is primarily used with strings, it can also reverse numbers, but remember, numbers are implicitly converted to strings before reversing.

SELECT REVERSE(12345) AS Result;

Output:

Result
--------------
54321

Creative Uses

Password Strength

You can introduce an additional layer of complexity in passwords by storing a combination of the original password and its reversed version.

Data Obfuscation:

While it’s not a secure encryption method, reversing strings can be one of the multiple steps in obfuscating data.

NOTE: Be cautious when reversing Unicode strings, especially those that have combining characters, as reversing might lead to unexpected results.

Conclusion

The SQL Server REVERSE function offers a handy way to manipulate string data. While it may seem like a simple tool, when combined with other SQL functions and constructs, it can become a powerful asset in your SQL toolkit.