The MySQL CHAR_LENGTH function is used to determine the number of characters in a given string. It is a character set-aware function, which means it takes into account the character set used for the string. The function returns the length of the string in characters, not bytes.

Syntax

Here’s the basic syntax of the CHAR_LENGTH function:

CHAR_LENGTH(str)

str: This is the input string for which you want to find the number of characters.

Example

Let’s look at a simple example:

SELECT CHAR_LENGTH('Hello, World!') AS character_count;

In this example, the function will return the number of characters in the string ‘Hello, World!’, which is 13. The result will be displayed in a column named character_count.

It’s important to note that CHAR_LENGTH is different from the LENGTH function in MySQL. The LENGTH function returns the length of a string in bytes, not characters. If you are dealing with multibyte character sets like UTF-8, the number of bytes may not be equal to the number of characters. In such cases, CHAR_LENGTH is preferred as it provides the character count.

Here’s a comparison between CHAR_LENGTH and LENGTH:

SELECT
    CHAR_LENGTH('Hello, World!') AS character_count,
    LENGTH('Hello, World!') AS byte_count;

In this example, you will see that the CHAR_LENGTH returns the number of characters, while LENGTH returns the number of bytes. This becomes more significant when dealing with multibyte character sets, where a single character may be represented by more than one byte.

In summary, the CHAR_LENGTH function in MySQL is a useful tool for determining the number of characters in a given string, considering the character set used, and is particularly handy when working with languages or character sets that include multibyte characters.