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PostgreSQL CREATE TABLE AS Keyword



The PostgreSQL CREATE TABLE AS keyword is used to create a table from an existing table by copying the existing table's columns. When creating a table in this way, the new table will be populated with the records from the existing table (based on the SELECT statement).

Syntax

The syntax for using CREATE TABLE AS keyword in PostgreSQL is given below:

/* copy all columns from a table */
CREATE TABLE new_table
  AS (SELECT * FROM old_table);

/* copy selected columns from a table */
CREATE TABLE new_table
  AS (SELECT column_1, column2, ...
      FROM old_table);

/* copy columns from multiple table */
CREATE TABLE new_table
  AS (SELECT column_1, column2, ...
      FROM old_table_1, old_table_2, ...);

Example:

Consider a database table called Employee with the following records:

EmpIDNameCityAgeSalary
1JohnLondon253000
2MarryNew York242750
3JoParis272800
4KimAmsterdam303100
5RameshNew Delhi283000
6HuangBeijing282800

  • Copy all columns of a table: The below statement is used to create a new table called Employee_PT by copying all columns of Employee table. The new table will contain those records of Employee table where the age of the employee is less than 28.

    CREATE TABLE Employee_PT
      AS (SELECT * FROM Employee
        WHERE Age < 28);
    
    -- see the result
    SELECT * FROM Employee_PT;
    

    This will produce the result as shown below:

    EmpIDNameCityAgeSalary
    1JohnLondon253000
    2MarryNew York242750
    3JoParis272800
  • Copy selected columns of a table: It is also possible to copy selected columns when using CREATE TABLE AS statement. In the example below, the columns which are copied are: EmpID, Name and City.

    CREATE TABLE Employee_PT
      AS (SELECT EmpID, Name, City FROM Employee
        WHERE Age < 28);
    
    -- see the result
    SELECT * FROM Employee_PT;
    

    This will produce the result as shown below:

    EmpIDNameCity
    1JohnLondon
    2MarryNew York
    3JoParis
  • Using AS clause: The AS clause can be used to rename the column name. See the example below:

    CREATE TABLE Employee_PT
      AS (SELECT EmpID, Name AS EmployeeName, City FROM Employee
        WHERE Age < 28);
    
    -- see the result
    SELECT * FROM Employee_PT;
    

    This will produce the result as shown below:

    EmpIDEmployeeNameCity
    1JohnLondon
    2MarryNew York
    3JoParis
  • Copy columns from multiple tables: Consider one more table called Contact_Info with the following records:

    Phone_NumberEmpIDAddressGender
    +1-80540980002Brooklyn, New York, USAF
    +33-1479961013Grenelle, Paris, FranceM
    +31-2011503194Geuzenveld, Amsterdam, NetherlandsF
    +86-10997324586Yizhuangzhen, Beijing, ChinaM
    +65-672348247Yishun, SingaporeM
    +81-3577990728Koto City, Tokyo, JapanM

    The below statement is used to create a new table called Employee_PT which will contain selected columns of Employee and Contact_Info tables. The new table will contain records based on INNER JOIN.

    CREATE TABLE Employee_PT
      AS (SELECT A.EmpID, A.Name, A.City, B.Address 
        FROM Employee A
        INNER JOIN Contact_Info B
        ON A.EmpID = B.EmpID);
    
    -- see the result
    SELECT * FROM Employee_PT;
    

    This will produce the result as shown below:

    EmpIDNameCityAddress
    2MarryNew YorkBrooklyn, New York, USA
    3JoParisGrenelle, Paris, France
    4KimAmsterdamGeuzenveld, Amsterdam, Netherlands
    6HuangBeijingYizhuangzhen, Beijing, China

❮ PostgreSQL Keywords