CREALE TABLE 表名 AS ＳＥＬＥＣＴ ．．．．．．．

１语法：

create table  表名 as select ..........

 

2用处：

是复制表结构和表数据

3例子：
（1*）

SQL> create table tt as select * from dept;

Table created.

SQL> select * from dept;

    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON

SQL> select * from tt;

    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON

SQL>

（2*）

SQL> create table ss as select * from dept where deptno=1;

Table created.

SQL> select * from ss;

no rows selected

SQL> select deptno from ss;

no rows selected

SQL> desc ss;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 DEPTNO                                             NUMBER(2)
 DNAME                                              VARCHAR2(14)
 LOC                                                VARCHAR2(13)

SQL>  desc tt;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 DEPTNO                                             NUMBER(2)
 DNAME                                              VARCHAR2(14)
 LOC                                                VARCHAR2(13)

SQL>

4总结：

能复制数据结构和数据  但where条件不成立的时候，只生产表结构。