run sql query on EXCEL and Access to get unique values

Question

I have 2 tables. One in Excel and one in Access. the Excel table contains around 5000 records and the Access Table contains around 50,000 records. At the excel table, I get new records all the time and I want to add only the new ones to the access database.
I really want to know how I can do that most efficiently, I thought about getting all the excel keys into an array then I just don't know how to get only what not in the access database.

Let's assume I have these records at my Excel and Access files:

Excel:

+-----+
| Key |
+-----+
| 123 |
| 124 |
| 125 |
| 126 |
+-----+

Access Table:

+-----+
| Key |
+-----+
| 123 |
| 124 |
| 125 |
+-----+

Result I want to achieve :

+-----+
| Key |
+-----+
| 126 |
+-----+

thank a lot, Lidor

Answer 1

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