Question

I have over 1,000 entries with duplicate values in an Access database. I want to create a column called Duplicate and set it to true if a record is NOT THE FIRST ONE with a particular value. This means, if the record is the first one with the value “Red Chair”, the Duplicate field is set to false, but all subsequent records with value “Red Chair” will have the Duplicate field set to true.

How do I perform this query in Access?

This database will be upsized to an SQL Server database, so an option for me is to ‘ignore’ the duplicate records while retrieving the records in my SQL query. If this option is viable, I’d like to know how to do this in SQL as alternative. Thanks.

Answer 1

You will have to use subqueries. Try this

UPDATE Tabelle1 SET Tabelle1.b = 'Duplicate'
WHERE 
((Tabelle1.[ID] In 
 (SELECT Tabelle1.[ID] FROM Tabelle1 WHERE 
  ((Tabelle1.[a] In 
     (SELECT [a] FROM [Tabelle1] As Tmp GROUP BY [a] HAVING Count(*)>1 )
   )
  AND 
  (Tabelle1.[ID] Not In 
    (SELECT min([id]) FROM [Tabelle1] as grpid GROUP BY [a] HAVING Count(*)>1)
  ));
)));