Need help merging multiple full SQL Server Backups into single database
SQL server doesn't have any built-in capacity to merge multiple backups into a single database, you'll have to restore each backup with a different database name (like WellProductionInjection_2019 and WellProductionInjection_2020), then do the work yourself to combine them however you need.
Once the databases are restored, you can combine them using a variety of tools; the simplest one is called the &quot;Import/Export Wizard&quot;. You can use this to copy entire tables from one database to another (if all tables have different names), or to append the data from table in one database to the tables in the other (if you actually want to combine the data into the same table).