Purging a Data Source
Be careful to select the radio button for one of the options; then provide the required information.
Query conditions. Select a field name, a comparison, and a value.
To add another condition to the list, change the drop-down at the right end from END to AND or OR. Enter left and right parentheses as needed.
If you change AND or OR back to END, all following conditions will be removed. You can "disable" a condition in the middle of the list by setting the Field drop-down list to --Select Field--.
Specifying date and time values
Duplicates. If the same value is found in the selected column of multiple records, remove all but one of those records.
Warning: You cannot determine which of the records will remain after the purge, so be sure you really want to leave only one of them in the data source.
Matching values. If the value in the selected column of the data source being purged is the same as the value in a specific column in a different table.
For example, you might use this option to clear a distribution list of recipients who've asked not to receive further campaigns by selecting the EMAIL field in both data sources.