got it, too many records to select from.
this may depedn on your deployment method but I was able to do this in a basic report creation.
create a command as your main data source (might work with a stored proc too)
in the command create a parameter matching your project codes field data type (likely numeric) and in the where clause use it in the command
e.g. WHERE table.projectcode = {?param}
now in the main report create a report param as a dynamic param
point the dynamic param to the subcode field (matching the data type)
in the report select criteria use the report param to filter the existing records that were already filtered via the command param.
e.g. table.subcodes = {?mainreportparam}
IN my test when you run or refresh the report you first get promted for the command param, then the prompt refreshed to give you a limited pick list based on your selection
Edited by DBlank - 24 Feb 2015 at 6:47am