find coumn name and his type with greatest size in bytes

[Алексей Ефимов <asefimov@xxxxxxxxx>]

Hello all! 
can you help, i need to write a query that displays column name with his data type that have maximum bytes length in row for every table in database:

for example, for table employees with data:

emp_id,  emp_name, emp_dept, emp_surname
1              alexey         2                trew

i need to get such output: 

table_name, emp_id,          column_name,  bytes, datatype

employees              1           emp_name       6         text