The ALTER TABLE statement can be used to modify an existing table by adding, altering, or dropping columns and indexes.
Syntax:- Add Column
ALTER TABLE table_Name
{
ADD
{
column_name data_type [ ( size ) ]
[ DEFAULT value ]
{ [ NULL | NOT NULL ] | [ { PRIMARY KEY | UNIQUE } ] }
{ [ CONSTRAINT constraint_name ] }
}
}
Examples
Code:
ALTER TABLE Product
ADD UnitPrice MONEY;
Output:
The command(s) completed successfully.
Syntax:- Alter Column
ALTER TABLE table_Name
{
ALTER COLUMN column_name
{
data_type [ ( size ) ] [ ( precision [ , scale ] ) ]
[ NULL | NOT NULL ]
}
}
Examples
Code:
ALTER TABLE Product
ALTER COLUMN Item_Count INT;
Output:
(1 row(s) affected)
Syntax:- Delete Column
ALTER TABLE table_Name
{
DROP { COLUMN column_name | [ CONSTRAINT ] constraint_name }
}
Examples
Code:
ALTER TABLE Product
DROP COLUMN Discount_Price;
Output:
The command(s) completed successfully.
