Queries :: Return Result When No Records Are Found?

Any way to build something into a sub-query that says 'if no records are found, return '0' or some other string'?

Otherwise is there a way to make a master query ignore sub-queries if they return no records?

Allow me to explain in more detail: I have a series of sub-queries, most of these take the sum of several fields from a number of different tables, and I have a main query which combines all of these, to be used as the basis of a summary report.

These queries aren't a problem, but I have a few other essential queries which take the modal (most common....) entry for fields which aren't numerical. So I can't use the sum function.

Now, if all the sub-queries are working then so does the main query, however if one of them fails to find a result, then none of them show up in the main query. I don't know why.

The issue is that depending on the date range selected, some of the tables targeted by the sub-queries don't have any records at all, so when they are run they return nothing. The sum queries can handle this since they just return 0, but those searching for modal records just find nothing (not 0's and not null fields, just blank across all rows).

Here's an example of my sql statement for the modal queries.

Code:
SELECT TOP 1 Trends.Trend AS ModeTboxTalk, "1" AS [Key]
FROM Trends INNER JOIN [Toolbox Talks] ON Trends.TrendID = [Toolbox Talks].TrendID
GROUP BY Trends.Trend, [Toolbox Talks].TrendID, [Toolbox Talks].TalkDate

HAVING ((([Toolbox Talks].TalkDate)<=[Forms]![WeeklyReportSelect]![WeekBox] And ([Toolbox Talks].TalkDate)>[Forms]![WeeklyReportSelect]![WeekBox]-7) AND (([Toolbox Talks].SiteID)=[Forms]![WeeklyReportSelect]![SiteBox]))

ORDER BY Count([Toolbox Talks].TrendID) DESC;

- FYI the weekly select form is where users select the week and site they want to report against. So it would be really peachy if I could tell the above to say something like 'no trend this week' if indeed there were no records.