how to add column in table in sql code example

Example 1: sql add column

ALTER TABLE Customers
ADD Email varchar(255);

Example 2: alter table add column

ALTER TABLE table
ADD COLUMN column VARCHAR (255) NOT NULL AFTER column;

Example 3: sqlserver add column to table

ALTER TABLE dbo.doc_exa 
ADD column_b VARCHAR(20) NULL, 
	column_c INT NULL ;