SQL alter table add column

Author(s): by Katie Glownia & by Emil Glownia


In this tutorial lesson I will show you how to use SQL add column command that will add new column to existing table. Our example will be presented using MS SQL Server 2008 R2.

SQL Add Column overview

Before we go into the details let me just say that adding a column is relatively easy; we just need to start with ALTER TABLE and specify the table name (if you use more than one schema in your database you will also have to specify it) after that we'll just need to use SQL Server ALTER TABLE Add column command and specify column properties. Below I will describe column properties you can set:

Column Name - This is obviously mandatory.
Column Date Type - This property is also mandatory and describes the type of values you want to store in the new field.
"Allow NULLs" - This property tells us if the field is mandatory or not and Accepts two values NULL or NOT NULL. If you omit this property a default setting will be used which NULL and means the field is not mandatory (optional).
There are several other popular column properties that you can add to your statement like defaul value, constraint, enable/disable trigger.

SQL Add column examples

In our example we will use the table below (‘Person’) in database ‘tutorial’ and using SQL Server ALTER TABLE Add column ‘PersonCity’.

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