SQL Server ALTER TABLE ADD Column

In this tutorial, you will learn how to use SQL Server ALTER TABLE ADD statement to add one or more columns to a table.

The following ALTER TABLE ADD statement appends a new column to a table:

ALTER TABLE table_name
ADD column_name data_type column_constraint;

In this statement:

• First, specify the name of the table in which you want to add the new column.
• Second, specify the name of the column, its data type, and constraint if applicable.

If you want to add multiple columns to a table at once using a single ALTER TABLE statement, you use the following syntax:

ALTER TABLE table_name
ADD 
    column_name_1 data_type_1 column_constraint_1,
    column_name_2 data_type_2 column_constraint_2,
    ...,
    column_name_n data_type_n column_constraint_n;

In this syntax, you specify a comma-separated list of columns that you want to add to a table after the ADD clause.

SQL Server ALTER TABLE ADD column examples

The following statement creates a new table named sales.quotations:

CREATE TABLE sales.quotations (
    quotation_no INT IDENTITY PRIMARY KEY,
    valid_from DATE NOT NULL,
    valid_to DATE NOT NULL
);

To add a new column named description to the sales.quotations table, you use the following statement:

ALTER TABLE sales.quotations 
ADD description VARCHAR (255) NOT NULL;

The following statement adds two new columns named amount and customer_name to the sales.quotations table:

ALTER TABLE sales.quotations 
    ADD 
        amount DECIMAL (10, 2) NOT NULL,
        customer_name VARCHAR (50) NOT NULL;

In this tutorial, you have learned how to use the SQL Server ALTER TABLE ADD statement to add one or more columns to a table.