alter table alter column sql server code example

Example 1: sql change column types

ALTER TABLE table_name
ALTER COLUMN column_name datatype;

-- Example
ALTER TABLE product
ALTER COLUMN description VARCHAR(250);

Example 2: sql add column

ALTER TABLE Customers
ADD Email varchar(255);

Example 3: sql server alter column

ALTER TABLE table_name 
ALTER COLUMN column_name new_data_type(size);

Example 4: alter table modify column

-- ORACLE 18c
ALTER TABLE table_name 
MODIFY column_name datatype;

-- Example
ALTER TABLE product
MODIFY description VARCHAR2(500 char);

Example 5: alter table query sql server change column

ALTER TABLE table_name
  ALTER COLUMN column_name column_type;

Example 6: sql alter table

-- With check if field already exists

IF NOT EXISTS(SELECT 1 FROM sys.columns 
          WHERE Name = N'Email'
          AND Object_ID = Object_ID(N'dbo.Customers'))
BEGIN    
	ALTER TABLE Customers
    ADD Email varchar(255);
END