MySQL LENGTH() Function

The LENGTH() function in MySQL calculates the length of a string, returning the number of bytes the string occupies. This is important because the number of bytes can differ from the number of characters, particularly when dealing with multi-byte character sets.

LENGTH(): Definition and Usage

LENGTH() is used to determine the size of strings in bytes. This can be essential for tasks such as data validation, string formatting, or operations that depend on string length. Keep in mind that a single character might use more than one byte depending on the character set (UTF-8, for example, uses multiple bytes per character for many characters).

Syntax

Syntax

LENGTH(string)

Parameter Values

Parameter Description
string The string whose length you want to determine. This is required.

Examples

Finding the Length of a String Literal

This example finds the length (in bytes) of the string "SQL Tutorial".

Syntax

SELECT LENGTH("SQL Tutorial") AS LengthOfString;
Output

12

Finding the Length of Strings in a Column

This example shows how to get the length (in bytes) of each 'CustomerName' from the 'Customers' table (assuming a table named 'Customers' exists with a 'CustomerName' column).

Syntax

SELECT LENGTH(CustomerName) AS LengthOfName
FROM Customers;
Output

LengthOfName
-------------
(The length, in bytes, of each customer name from the Customers table will be displayed here.)
**Note:** The output of the second example will vary based on the data in your `Customers` table and the character set used. Each row will show the byte length of the corresponding `CustomerName`. The byte length might differ from the character count if multi-byte characters are used.