Thanks for the suggestions -- it hadn't occurred to me to use a parameter tracking table like that. It's a useful tool. As regards the logic suggestion, my sproc was using something like that already, but thank you anyway.

The problem was in an unexpected place. The end result of the sproc was to return the following result set:

IF @intmg>0

BEGIN

SELECT 'All' AS RegionID

,'All Regions' AS Region

UNION ALL

SELECT DISTINCT Regionshort

,RegionShort

FROM dimdistributors

END

ELSE

BEGIN

SELECT DISTINCT Regionshort

,RegionShort

FROM dimdistributors

WHERE RegionShort=@strRegion

END

But the query in the ELSE statement (the one that 'wasn't working') did not alias the columns, so the dataset in the report wasn't being populated. When I added aliases as below, everything got cleaned up.

IF @intmg>0

BEGIN

SELECT 'All' AS RegionID

,'All Regions' AS Region

UNION ALL

SELECT DISTINCT Regionshort

,RegionShort

FROM dimdistributors

END

ELSE

BEGIN

SELECT DISTINCT Regionshort AS RegionID

,RegionShort AS Region

FROM dimdistributors

WHERE RegionShort=@strRegion

END

Thanks again! David