Learn how to use SQL ALTER TABLE statement with the explained example of this tutorial. Add, delete or modify the table columns using the SQL ALTER TABLE statement.

You can add more columns to the table or you can change the name of the column. In addition to this, you can also delete the column using the SQL ALTER TABLE statement.

This is the single statement by which you can perform multiple tasks with the column of the table.

How to Use SQL ALTER TABLE Statement to Add, Delete or Modify Columns

You just need to specify the table name and the columns you want to delete or change using the ALTER table method. Also, you can rename the name of the columns using this statement. The method is very useful in all respect to manipulate the column of a table.

ADD Column Using SQL ALTER TABLE Statement

Add more columns to a table using the syntax given below. The syntax contains the table name and the column name with the data type. You have to use the ADD statement after the table name. Then after you have to specify the data type of the column.
Syntax

DROP Column Using SQL ALTER TABLE Statement

Delete the column of the table using the DROP COLUMN statement with the ALTER statement. In this, you have to specify the table name from which you want to remove the column. Also, you have to specify the column name which you want to delete from the specified table.
Syntax

MODIFY Column Using SQL ALTER TABLE Statement

Change the name of the column using the syntax given below. You need to only specify the table name and after this, you have to use the MODIFY COLUMN statement. Also, specify the column name with the data type to which you want to modify the column.
Syntax

RENAME Column Using SQL ALTER TABLE Statement

Rename the column name of the table using the syntax given below. To change the column name you have to specify the old column and the new column name to which you want to change the column name.
Syntax

Parameter Descriptions

Sr.No. Parameter Name Description
1 new_tablename Put new table name to which you want to manipulate the column.
2 old_column_name Enter the name of the old column which you want to modify, delete or change.
3 data_type Specify the data type of the new column name that you want to add or modify on the selected table.

Examples to Use SQL ALTER TABLE Statement


The above example adds one column to the table Employee. I have also specified the table name to which I want to add the column.


The above example deletes the Address column from the specified table name.


The above example changes the data type of the Address column from varchar to character.


The above example changes the column name from Address to Place.

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