There are few ways to add a column to Magento's core grids or other grids i.e. sales order.

The possible two ways are

1. using plugin to join on sales order grid collection with other tables (see my answer here)
2. create a column in sales_order_grid table and save values in that column for an order. (see Sergey's post)

There are few ways to add a column to Magento's core grids or other grids i.e. sales order.

The possible two ways are

1. using plugin to join on sales order grid collection with other tables (see my answer here)
2. create a column in sales_order_grid table and save values in that column for an order. (see Sergey's post)