In the Caché database, when calculating the total count based on the unique identifier of a record, the quantity is over 1.2 million. After removing duplicates based on the unique identifier and then calculating the total count, the quantity is over 400,000. When grouping by the unique identifier, it can be observed that the count for this identifier is not one. However, when performing a conditional query based on the identifier, only one record can be retrieved. Why is this the case?