Introduction:

In this article we will explain how to alter a table in SQL Server or how to rename column name or change column data type by using alter table statement in SQL Server with Example.

Description:

The ALTER TABLE statement is used to add, modify or delete columns in an existing table. It is also used to rename a table.

You can also use SQL ALTER TABLE command to add and drop various constraints on an existing table.

SQL Alter Table Add Column

If you want to add columns in SQL table, to use the following SQL alter table syntax:

ALTER TABLE table_name ADD column_name datatype;


Example:

ALTER TABLE employee ADD Address nvarchar(500);


        SQL Alter Table Modify Column

        If you want to modify an existing column data type in SQL table, to use the following SQL alter table syntax:

ALTER TABLE table_name ALTER COLUMN column_name datatype;

 

Example:

 

ALTER TABLE employee ALTER COLUMN Address nvarchar(750); 

       

        SQL Alter Table DROP Column

        If you want to delete an existing column in SQL table, to use the following SQL alter table syntax:

ALTER TABLE table_name DROP COLUMN column_name;  

Example:

ALTER TABLE employee DROP COLUMN Address;

I hope this article will help to you.


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