Use Case Accelerators > How to Deduplicate Data Using Aggregation

How to Deduplicate Data Using Aggregation

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Summary

One method for eliminating duplicate records in DMExpress is to use aggregation and keep only the first, last, or any record from a set of equal-keyed records.

Resolution

Duplicate records can be eliminated in DMExpress using aggregation with the First, Last, or Any function to keep the first, last, or any of each field from a set of duplicate records. The First and Last functions have an impact on performance, so only choose those options when the records are ordered and keeping the first or last is necessary. The Any function does not guarantee that all fields will come from a single record.

Attachments

143_DeduplicateUsingAggregation.zip, compatible with DMExpress version 8.0.5 or higher

Additional Information

Deduplication can also be achieved using sort. Consider the following when choosing between the aggregation and sort methods:

For more information on summarization functions available in a DMExpress Aggregate task, see Summarization Functions in the DMExpress Help.

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