Returns the number of characters, instead of the number of bytes, of the given string expression, excluding trailing blanks.
LEN (string_expression )
The string expression to be evaluated. The string_expression argument can be any data type that can be implicitly converted to nvarchar. Binary expressions can also be supplied as arguments, in which case the number of bytes is returned.
The following example returns the company names listed in the Customers table and the number of characters in the company name.
SELECT [Company Name], LEN([Company Name]) AS Expr1
LEN function does not support the following data types.