drupal views3 aggregation

How to use the "aggregation" settings of views3 in drupal 7.It is about the advanced options in Views 3. The aggregation setting makes Views return aggregated values for advanced reporting. Views3 aggregation could be used for count the number of items baked into each row, or sum them up, or calculate their average, or count the number of unique items etc. You might need this to generate a source for graphical representation of your data.

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