DATALENGTH (Transact-SQL)
Returns the number of bytes used to represent any expression.
Syntax
DATALENGTH ( expression )
Return Types
bigint if expression is of the varchar(max), nvarchar(max) or varbinary(max) data types; otherwise int.
Remarks
DATALENGTH is especially useful with varchar, varbinary, text, image, nvarchar, and ntext data types because these data types can store variable-length data.
The DATALENGTH of NULL is NULL.
Note
Compatibility levels can affect return values. For more information about compatibility levels, see ALTER DATABASE Compatibility Level (Transact-SQL).
Examples
The following example finds the length of the Name column in the Product table.
USE AdventureWorks2008R2;
GO
SELECT length = DATALENGTH(Name), Name
FROM Production.Product
ORDER BY Name;
GO