Create a table with the same hooks in Oracle

Creating tables in Oracle to hook the same or consistent tables can also be used in many cases. Convenient.

For example, a department table exists as follows:

 
 

  
  
SQL> select * from dept;  
  
  
   
  
  
DEPTNO DNAME          LOC  
  
  
------ -------------- -------------  
  
  
    50 TRAIN          BOSTON  
  
  
    60 MARKET           
  
  
    10 ACCOUNTING     NEW YORK  
  
  
    20 RESEARCH       DALLAS  
  
  
    30 SALES          CHICAGO  
  
  
    40 OPERATIONS     BOSTON  
  
  
   
  
  
6 rows selected  
  
  
  
 
 

Create a table with the same department table, that is, a table with the same name except the table name and the other five dirty tables, as shown below:

 
 

  
  
SQL> create table new_dept as select * from dept;  
  
  
   
  
  
Table created  
  
  
   
  
  
SQL> select * from new_dept;  
  
  
   
  
  
DEPTNO DNAME          LOC  
  
  
------ -------------- -------------  
  
  
    50 TRAIN          BOSTON  
  
  
    60 MARKET           
  
  
    10 ACCOUNTING     NEW YORK  
  
  
    20 RESEARCH       DALLAS  
  
  
    30 SALES          CHICAGO  
  
  
    40 OPERATIONS     BOSTON  
  
  
   
  
  
6 rows selected  
  
  
  
 
 

If you do not like the data in the newly created table. You only need to have the same table attributes. You can add a condition: rownum = 0 or rownum <1 is as follows:

 
 

  
  
SQL> create table new_dept1 as select * from dept where rownum<1;  
  
  
   
  
  
Table created  
  
  
   
  
  
SQL> select * from new_dept1;  
  
  
   
  
  
DEPTNO DNAME          LOC  
  
  
------ -------------- -------------  
  
  
SQL>  create table new_dept2 as select * from dept where rownum=0;  
  
  
   
  
  
Table created  
  
  
   
  
  
SQL> select * from new_dept2;  
  
  
   
  
  
DEPTNO DNAME          LOC  
  
  
------ -------------- -------------  
 
 

In this way, sometimes it is much easier to import data for testing.