Retrieve by inserting ORDER of Merged table in SQL Server
Databases do not store data "in order" (for the most part).

If you want data out in a specific order, you must supply an appropriate ORDER BY clause.



In your data model:


BASE_Invoice is a transaction.
BASE_Payment is a transaction.


You're missing a table that holds the information for a transaction.  That table will include all columns common to both types of transactions, a transaction ID (PK) for all types of transactions, and information about the transaction that can be used by the ORDER BY clause.

It some cases, the Transaction ID could be used to determine ORDER BY.  In other cases, you may need to include a timestamp column to be used by the ORDER BY clause.