MySQL String Length Function

MySQL provides us with a collection of tools and built-in functions for manipulating various data types and records in a database. Some common and useful functions are String functions and operators.

In this tutorial, we shall look at how to use pre-defined MySQL functions to determine the length of a string.

The Basics

Without diving deep into character sets, MySQL supports a wide selection of character sets. Each character set contains a maximum length of bytes it can store per character.

To learn more about the supported character set and their maximum length, use the resource provided below:

In MySQL, a string can be in any of the supported character sets. To determine the length of a string, you can use the bytes method or the character method.

The bytes method returns the length of the specified string in bytes. If a string contains a set of 1-byte characters, the length of the string is equal to the number of characters.

However, if the specified string contains multi-byte characters, the number of the characters is not equal to the length of the string.


To get the length of a string in characters, you can use the CHARACTER_LENGTH() function. This function is a synonym of the CHAR_LENGTH() function. It works by counting the number of characters in a string regardless of whether it’s a single-byte or multi-byte character.

Let us take the country table in the sakila database. To get the length of country name strings, we can use a query as:

SELECT country, char_length(country) AS length
FROM country
ORDER BY length

The above query should return the length of country names.


To get the length of a string in bytes, we use the LENGTH() function. In this case, the function takes into account whether it’s a single-byte or multi-byte character.

We can apply the above example as shown in the query below:

SELECT country, LENGTH(country) AS length
FROM country
ORDER BY length

In this example, the values are in bytes instead of characters. Since the above examples use single-byte characters, you may not notice the difference.

However, on a multi-byte character as the Kanji value for the country, the values are different.

Consider the query below:

SELECT CHAR_LENGTH('国') AS length_in_char;

Once we run the above query, we should get the length as 1.

| length_in_char |
|              1 |

Consider the same query using the length() function.

SELECT LENGTH('国') AS length_in_bytes;

In this case, the length is 3.

| length_in_bytes |
|               3|


This guide has shown you how to use the built-in MySQL functions to get the length of a string in bytes and characters.

Thank you for reading!

About the author

John Otieno

My name is John and am a fellow geek like you. I am passionate about all things computers from Hardware, Operating systems to Programming. My dream is to share my knowledge with the world and help out fellow geeks. Follow my content by subscribing to LinuxHint mailing list