Use this function to determine the length of a string. For example, specify a column name for string-expression to determine the length of values in the column.
If the string contains multibyte characters, and the proper collation is being used, LENGTH returns the number of characters,
not the number of bytes. If the string is of data type BINARY, the LENGTH function behaves as the BYTE_LENGTH function.
You can use the LENGTH function and the CHAR_LENGTH function interchangeably for CHAR, VARCHAR, and LONG VARCHAR data types.
However, you must use the LENGTH function for BINARY and bit array data types.
The LENGTH function is a vendor extension; however, its semantics are identical to that of the CHAR_LENGTH function in
the SQL/2008 standard. Using LENGTH over a string expression of type NCHAR comprises part of optional SQL/2008 language feature