SQL & PL/SQL :: Insertion Of Data From One To Other Schema Table In Same Database

I need to insert data from one schema table to other schema's table in same database.The thing is columns are not equal.so when I am trying to use insert statement it is throwing error as not enough values. The situation is explained clearly below.The insert stmt is implemented in second schema whose table name is b.

SQL> create table a(ID_A NUMBER,Name varchar2(10),rollno NUMBER,address varchar2(10));
Table created.
SQL> insert into a(ID_A,Name,rollno,address)values(1,'ravi', 101,'hyd');

1 row created.

SQL> insert into a(ID_A,Name,rollno,address)values(2,'rav', 102,'delhi');

1 row created.
SQL> insert into a(ID_A,Name,rollno,address)values(3,'ra', 103,'chn');

1 row created.

SQL> create table b(ID NUMBER,Name varchar2(10),rollno NUMBER,address varchar2(1
0),route varchar2(10),direction varchar2(10));

Table created.
SQL> ALTER TABLE B ADD
2 CONSTRAINT B_PK1
3 PRIMARY KEY
4 (ID);

Table altered.
SQL> create sequence b_seg start with 1;

Sequence created.
SQL> insert into b select b_seg.nextval,lexcom.a.* from lexcom.a,dual;
insert into b select b_seg.nextval,lexcom.a.* from lexcom.a,dual
*
ERROR at line 1:
ORA-00947: not enough values

So,for table b in ID column sequence needed to be inserted and other columns need to be taken from table a.I can understand the error is because two tables are not having equal columns.So,the insert stmt is throwing error.

I can manually write by taking columns from a and b and write insert stmt as follows,but this is tedious process.

SQL> insert into b(ID,Name,rollno,address)select b_seg.nextval,lexcom.a.Name,lex
com.a.rollno,lexcom.a.address from lexcom.a,dual;

3 rows created.

But this is time taking and I had tables which has many columns to be inserted.So is there any other way to solve it and implement insert stmt.