CREATE TABLE AS Statement

The CREATE TABLE AS statement is used to create a table from an existing table by copying the columns of existing table.

Note: If you create the table in this way, the new table will contain records from the existing table.

Syntax:

1. CREATE TABLE new_table  
2. AS (SELECT * FROM old_table);   

Create Table Example: copying all columns of another table

In this example, we are creating a “newcustomers” table by copying all the columns from the already existing table “Customers”.

1. CREATE TABLE newcustomers  
2. AS (SELECT *   FROM customers  WHERE customer_id < 5000);  

Table created.

This table is named as “newcustomers” and having the same columns of “customers” table.

Create Table Example: copying selected columns of another table

Syntax:

CREATE TABLE new_table  

  AS (SELECT column_1, column2, ... column_n  

      FROM old_table);

Let’s take an example:

CREATE TABLE newcustomers2  

AS (SELECT customer_id, customer_name  

    FROM customers  

    WHERE customer_id < 5000);

The above example will create a new table called “newcustomers2”. This table includes the specified columns customer_id and customer_name from the customers table.

Create Table Example: copying selected columns from multiple tables

Syntax:

CREATE TABLE new_table  

AS (SELECT column_1, column2, ... column_n  

    FROM old_table_1, old_table_2, ... old_table_n);

Let’s take an example: Consider that you have already created two tables “regularcustomers” and “irregularcustomers”.

The table “regularcustomers” has three columns rcustomer_id, rcustomer_name and rc_city.

CREATE TABLE  "regularcustomers"   

   (    "RCUSTOMER_ID" NUMBER(10,0) NOT NULL ENABLE,   

    "RCUSTOMER_NAME" VARCHAR2(50) NOT NULL ENABLE,   

    "RC_CITY" VARCHAR2(50)  

   )  

/

The second table “irregularcustomers” has also three columns ircustomer_id, ircustomer_name and irc_city.

CREATE TABLE  "irregularcustomers"   

   (    "IRCUSTOMER_ID" NUMBER(10,0) NOT NULL ENABLE,   

    "IRCUSTOMER_NAME" VARCHAR2(50) NOT NULL ENABLE,   

    "IRC_CITY" VARCHAR2(50)  

   )  

/

In the following example, we will create a table name “newcustomers3” form copying columns from both tables.

Example:

CREATE TABLE newcustomers3  

  AS (SELECT regularcustomers.rcustomer_id, regularcustomers.rc_city, irregularcustomers.ircustomer_name  

      FROM regularcustomers, irregularcustomers  

      WHERE regularcustomers.rcustomer_id = irregularcustomers.ircustomer_id  

      AND regularcustomers.rcustomer_id < 5000);