Returns the number of characters of the specified string expression, excluding trailing blanks.
To return the number of bytes used to represent an expression, use the DATALENGTH function.
bigint if expression is of the varchar(max), nvarchar(max) or varbinary(max) data types; otherwise, int.
If you are using SC collations, the returned integer value counts UTF-16 surrogate pairs as a single character. For more information, see Collation and Unicode Support.
The following example selects the number of characters and the data in FirstName for people located in Australia.
USE AdventureWorks2012; GO SELECT LEN(FirstName) AS Length, FirstName, LastName FROM Sales.vIndividualCustomer WHERE CountryRegionName = 'Australia'; GO