PostgreSQL ADD Keyword

The PostgreSQL ADD keyword is used to add a column in an existing table.

Syntax

The syntax for using ADD keyword in PostgreSQL is given below:

ALTER TABLE table_name
ADD column_name;

Example:

Consider a database table called Employee with the following records:

• To add a new column EMail with datatype varchar(255) in the Employee table, the query is:

  ALTER TABLE Employee
  ADD EMail varchar(255);
  
  -- see the results
  SELECT * FROM Employee;
  

  
  

  This will produce the result as shown below:

  EmpID	Name	City	Age	Salary	EMail
  1	John	London	25	3000
  2	Marry	New York	24	2750
  3	Jo	Paris	27	2800
  4	Kim	Amsterdam	30	3100
  5	Ramesh	New Delhi	28	3000
  6	Huang	Beijing	28	2800

• To add a default value to the new column, DEFAULT constraint can be used. Consider the example below:

  ALTER TABLE Employee
  ADD Bonus DECIMAL(18,2) DEFAULT 1000;
  
  -- see the results
  SELECT * FROM Employee;
  

  
  

  This will produce the result as shown below:

  EmpID	Name	City	Age	Salary	Bonus
  1	John	London	25	3000	1000
  2	Marry	New York	24	2750	1000
  3	Jo	Paris	27	2800	1000
  4	Kim	Amsterdam	30	3100	1000
  5	Ramesh	New Delhi	28	3000	1000
  6	Huang	Beijing	28	2800	1000