how to add a column to table in sql code example

Example 1: sql add column

ALTER TABLE Customers
ADD Email varchar(255);

Example 2: sqlserver add column to table

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

Example 3: sql server add column

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