Gotcha. Incremental Load makes a lot of sense but Qlik doesn't have a UNION ALL which is why I thought you were doing that in MYSQL. I understand your confusion and will go through what the post meant by INNER JOIN
If you already have your years broken out then I would handle the Incremental Load on a Year by Year basis per the normal scheme.
Qlik now provides a MERGE to handle incremental loads more cleanly for integration with Change Data Capture, https://help.qlik.com/en-US/sense/February2021/Subsystems/Hub/Content/Sense_Hub/Scripting/ScriptPref... but it doesn't handle DELETES so you might as well stick with the known method.
Typically for Incremental load you would:
Read the new information into a table we will call it MyTable
Concatenate the old information into the new information table using a
WHERE NOT EXISTS (the where not exists forces you to keep the updated values)
INNER JOIN - The Inner Join is done within Qlik. The concept is:
Read all of the Primary keys from the databases into a table we will call it MyTableKeys
Now we do an Inner Join within Qlik Sense, (not the db) between MyTable and MyTableKeys. Thus removing any values that no longer exist in the database.
