create table emp_dept_txt as select first_name,last_name,email,phone_number,department_name from employees ,departments where employees.department_id=departments.department_id and 1=0;

SQL> select * from emp_dept_txt;
no rows selected

SQL> desc emp_dept_txt
Name Null? Type
----------------------------------------- -------- ----------------------------
FIRST_NAME VARCHAR2(20)
LAST_NAME NOT NULL VARCHAR2(25)
EMAIL NOT NULL VARCHAR2(25)
PHONE_NUMBER VARCHAR2(20)
DEPARTMENT_NAME NOT NULL VARCHAR2(30)

create table as select where 1=0會把null和not null屬性也帶上

相關文章