//Sql Server
//Add a table
ALTER TABLE clients ADD Points INT DEFAULT 0
//Edit an existing table
ALTER TABLE clients ADD CONSTRAINT points DEFAULT 0 FOR PointsALTER TABLE PERSON
ADD IS_ACTIVE VARCHAR2(1) DEFAULT 'N' NOT NULLCREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
City varchar(255) DEFAULT 'Sandnes'
);/*Adding a New Column, with default value to an existing table*/
ALTER TABLE (Table_Name)
ADD (Column_Name)(Data_Type) (Null/NOT NULL)
CONSTRAINT (Constraint_Name) DEFAULT (Default_Value)Sets a default value for a column;
Example 1 (MySQL): Creates a new table called Products which has a
name column with a default value of ‘Placeholder Name’ and an available_
from column with a default value of today’s date.
CREATE TABLE products (
id int,
name varchar(255) DEFAULT 'Placeholder Name',
available_from date DEFAULT GETDATE()
);
Example 2 (MySQL): The same as above, but editing an existing table.
ALTER TABLE products
ALTER name SET DEFAULT 'Placeholder Name',
ALTER available_from SET DEFAULT GETDATE();CREATE TABLE College (
college_id INT PRIMARY KEY,
college_code VARCHAR(20),
college_country VARCHAR(20) DEFAULT 'US'
);