If you are getting
Non-Unique value/primary key (or sql_distinct_key), value overflow or collision when computing sum error and you've checked that you have a primary key and are also using a sum_distinct with sql_distinct_key, you should check to make sure your sql_distinct_key only has one corresponding value in SQL.
First check SQL runner to see if you're getting a crazy high number (e.g 1.22222e^32)
If so, run this sql query in SQL runner to see if there are any counts higher than 1.
FROM demo_db.order_items AS order_items
GROUP BY 1
ORDER BY 3 DESC
You can double-check this by going back to the Explore and filtering on the offending sql_distinct_key, choosing the corresponding sql field and seeing how many rows appear in the Explore.