|expression||An expression, which can be the name of a column, a string literal, or the result of another scalar function. The underlying data type can be a character type (such as CHAR or VARCHAR), a numeric, or a data stream.|
The DATALENGTH, CHAR_LENGTH, and CHARACTER_LENGTH functions are identical. Use of the CHAR_LENGTH function is recommended for new code. DATALENGTH is provided for TSQL compatibility. Refer to CHAR_LENGTH for further details.