Question

What value is assigned to a Nullable field if it's value is not assigned in the INSERT INTO statement?

Answer 1

if an INSERT or REPLACE statement includes no value for the column,the column is NULL, MySQL handles the column according to the SQL mode in effect at the time.
If strict SQL mode is not enabled, MySQL sets the column to the implicit default value for the column data type.
If strict mode is enabled, an error occurs for transactional tables and the statement is rolled back. 
it is according to the manual which is in my school library

Answer 2

Answer:

IF AN INSERT OR REPLACE STATEMENT INCLUDES BO VALUE FOR THE XOLUMB , THEN THE VAKUE FOR THE COLOUMN IS ASSINGED TO BE NULL

HOPE IT HELPS !!