How to use modify in sql

MODIFY statement is used to modify the table structure, including adding, deleting or modifying columns. The steps are as follows: Specify the table name to be modified. Specify the column name to be modified. Specifies the new data type of the column. Optional: Specify columns that do not allow null values. Optional: Specify the default value for the column.

Usage of MODIFY in SQL

Overview

MODIFY Statements are used in SQL to modify the table structure. It allows you to add, delete, or modify a table's columns.

Syntax

MODIFY TABLE table_name
MODIFY column_name data_type [NOT NULL] [DEFAULT default_value];

Parameters

• table_name: The name of the table to be modified .
• column_name: The name of the column to be modified.
• data_type: The new data type of the column.
• NOT NULL: Optional. If specified, the column will not allow null values.
• DEFAULT default_value: Optional. If specified, the column will get the specified default value.

Usage

Modify column data type

MODIFY TABLE customers
MODIFY age INT;

Add column

MODIFY TABLE products
ADD COLUMN description VARCHAR(255);

Delete column

MODIFY TABLE orders
DROP COLUMN shipping_address;

Modify column default value

MODIFY TABLE employees
MODIFY salary DECIMAL(10, 2) DEFAULT 1000;

Note

• MODIFY statement cannot be used to modify primary key columns.
• In some database systems, the syntax of the MODIFY statement may be slightly different. See your specific database documentation for details.

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