MySQL LENGTH() Function

Return the length of the string, in bytes:

SELECT LENGTH("SQL Tutorial") AS LengthOfString;

Definition and Usage

The LENGTH() function returns the length of a string (in bytes).

LENGTH(string)

Parameter	Description
string	Required. The string to count the length for

Works in:	From MySQL 4.0

Return the length of the text in the "CustomerName" column, in bytes:

SELECT LENGTH(CustomerName) AS LengthOfName
FROM Customers;