You may wonder when you use the function LEN() to get the length of the ntext or image field, you will get an error. This is because the LEN() function is only used to get the length of the nvarchar, varchar or char field types only.

To get the length of the ntext or image field type, you can use the DATALENGTH() function, see below example:

SELECT DATALENGTH(FIELD_NAME) FROM TABLE_NAME