SQL Server DATALENGTH() Function

Return the length of an expression (in bytes):

SELECT DATALENGTH('W3Schools.com');

Definition and Usage

The DATALENGTH() function returns the number of bytes used to represent an expression.

Note: The DATALENGTH() function counts both leading and trailing spaces when calculating the length of the expression.

Tip: Also see the LEN() function.

DATALENGTH(expression)

Parameter	Description
expression	Required. The data type to return the length for. If expression is NULL, it returns NULL

Works in:	SQL Server (starting with 2008), Azure SQL Database, Azure SQL Data Warehouse, Parallel Data Warehouse

Return the length of an expression (in bytes) (counts both leading and trailing spaces):

SELECT DATALENGTH(' W3Schools.com ');

Return the length of an expression (in bytes):

SELECT DATALENGTH('2017-08');