How to Resolve MySQL Error 1062 (Duplicate Entry 'NULL') During Database Migration

Database migration is a common task for developers when moving a live site to a development server.

However, during the import process, you may encounter the MySQL Error 1062, specifically the error message:

Duplicate entry 'NULL' for key 'sales_order_grid.SALES_ORDER_GRID_PICKUP_LOCATION_CODE'.

This error often occurs when there are records with 'NULL' values in the key column of the specific table mentioned in the error message.

In this blog post, we will discuss how to resolve this issue and successfully import your SQL file.

Resolving the Duplicate Entry 'NULL' Error:

To fix the duplicate entry 'NULL' error, you need to modify the table structure and remove the duplicate entries or update the 'NULL' values.

In this case, we will focus on the 'sales_order_grid' table.

Before making any changes, it is always recommended to take a backup of your database to ensure the data integrity in case you need to revert.

Inspect the 'sales_order_grid' table and identify the records that have 'NULL' values in the 'pickup_location_code' column.

These records are causing the duplicate entry error.

To resolve the issue, you can either update the 'NULL' values in the 'pickup_location_code' column or set a default non-NULL value for those records.

This depends on the logic and requirements of your application.

Once the 'NULL' values are updated or replaced, the duplicate entry error will be resolved.

After updating the 'sales_order_grid' table, attempt to import the SQL file again using the CLI command:


mysql -u "user" -p "database" < importfile.sql

If the NULL values have been properly handled, the import process should now proceed without any duplicate entry errors.

Handling MySQL Error 1062, specifically the duplicate entry 'NULL' error, during database migration can be frustrating.

Remember, always take backups and test the migration on a development environment before applying it to your live site.