sql alter table

1ALTER TABLE Customers
2ADD Email varchar(255);
3

1ALTER TABLE table_name
2ADD column_name datatype;
3
4--example
5ALTER TABLE Customers
6ADD Email varchar(255);

1ALTER TABLE table_name
2ADD column_name datatype;

1ALTER TABLE dbo.doc_exa 
2ADD column_b VARCHAR(20) NULL, 
3	column_c INT NULL ;

1ALTER TABLE table
2ADD COLUMN column VARCHAR (255) NOT NULL AFTER column;

1-- With check if field already exists
2
3IF NOT EXISTS(SELECT 1 FROM sys.columns 
4          WHERE Name = N'Email'
5          AND Object_ID = Object_ID(N'dbo.Customers'))
6BEGIN    
7	ALTER TABLE Customers
8    ADD Email varchar(255);
9END