This should point you in the right direction...<br>
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You can use the DateDiff function in your query. Create a new column that has the following Field definition:<br>
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Diff: DateDiff("h",[StartDate],[EndDate])<br>
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Your query will have a new field called "Diff" that represents the number of hours between the start & end date.<br>
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Look-up DateDiff in help to get more info.<br>