Creating table using query: – We also create a table by specifying some additional information such as using not null or using query. We can use additional information with create statement as follows.

                Create table company(ename varchar2(10) not null,cname varchar2(10),salary number(7,2) not null,jdate date);

After creating the above table, it is impossible to insert row without ename and salary column.

                Create table company as select ename,cname,salary from employee;

The above table company created same as table employee with ename,cname, and salary column.