Determine Outflow by comparing counts on different days
I have a table that has 2 fields: Account Number and Date Completed. I want to check if an Account Number on a given date exists on the following date. If it exists, I can flag it as NOT complete. If it does not exist, I can flag it as complete. Can anyone help me with the code that I can put in the load script that would allow me to do this? In the example below, the account 12340 on 1/5/15 would be flagged as 'complete' because it doesn't exist in the next existing date, which is 1/8/15.