After a shopping trip to IKEA, this will only take about 5 minutes to assemble. Total cost: 80 Dollars/ Euros
Get two of these
Use three furniture connectors and add washers to each end
Put both tables back to back and attach them to each other using the furniture connectors.
You can use the wholes that are already in the table, no need to drill...
The finished table.
Both sides easily fold flat whenever you don't need the table. You can easily put it aside
If you like the table, have a look what you can do with the ÄPPLARÖ bench & chairs: https://snapguide.com/guides/use-your-outdoor-furniture-as-a-wardrobe-in-winter