I am not sure what you want.
You insert a whole row. A row is always complete. So the other fields do
have to have a value of some sort. If you do not specify a value for
them, the default value is used. If no default value is specified in the
table, NULL is the ultimate default and is used.
Very new versions of MySQL seem to have a restrict policy that I am used
to with other databases: If a row is set to NOT NULL and no default is
given, a value must be specified during insert or the insert is
rejected. Older versions of MySQL would insert the standard default
value for the data type (0 for numbers, '' for strings)