The difference between Len () and Datalength () in Mysql _mysql

LEN (string_expression) parameter: string to be evaluated
Returns the number of characters for the specified string expression, which does not contain trailing spaces.
bigint If the expression data type is varchar (max), nvarchar (max), or varbinary (max);
The ntext field cannot be evaluated

DATALENGTH (expression) parameter: An expression of any data type
Returns the number of bytes used to represent any expression.
Returns bigint if the expression data type is varchar (max), nvarchar (max), or varbinary (max) data type, otherwise int.
For varchar, varbinary, text, image, nvarchar, and ntext data types, datalength is especially useful because these data types can store variable-length data.
The result of the null datalength is null.