How to Insert a Duplicate Row into a SQL Table with a New ID

Learn how to insert a duplicate row into a SQL table while assigning it a new unique ID. This technique is useful for SQL Server users who need to replicate existing records for various purposes.
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How to Insert a Duplicate Row into a SQL Table with a New ID

When working with a SQL database, there might be occasions when you need to duplicate an existing record while assigning it a new unique ID. This task is quite common in situations where a template or prototype record needs to be replicated. Here’s how you can accomplish this in SQL Server using the INSERT INTO statement.

Step-by-Step Guide

Identify the Source Row: First, you need to determine the row you want to duplicate. For example, let's assume you have a table named Employees and you want to duplicate the row where the EmployeeID is 5.

Choose Columns to Insert: Identify which columns you want to duplicate from the source row. Always exclude the primary key column if it’s auto-incremented or will be manually assigned a new value.

Compose the Insert SELECT Statement:

Use SELECT to retrieve the columns from the row you want to duplicate.

Use INSERT INTO to insert these values into the same table, while manually specifying the new ID if needed.

Example SQL Query

Here is an example of how the query might look:

[[See Video to Reveal this Text or Code Snippet]]

Explanation:

NEWID(): If the EmployeeID is a uniqueidentifier, it will generate a new unique ID.

EmployeeID = 5: This is the condition to identify the row you want to duplicate.

Common Use Cases

Prototyping Records: Create a prototype employee or product that serves as a template for new entries.

Testing: During development, duplicating rows can help generate test data.

Versioning: Maintain versions of records by duplicating an existing row and making modifications.

Considerations

Ensure that the ID column is properly handled, especially if it is not an auto-increment field.

Validate other column constraints to prevent violations (like NOT NULL constraints, Unique constraints, etc.).

By following this approach, you can efficiently duplicate rows in your SQL tables while ensuring each row gets a new unique identifier. This is particularly useful for maintaining data consistency and integrity in your database operations.