SSRS 2008 R2 multi valued parameter with different display values and different database values

Hi All,

I have a scenario where I have a multi valued parameter in SSRS 2008 R2. The values in the parameter have been generated from a dataset query. I need to have a different value to be displayed instead of a value. eg: In the database the value is 'ABC' , but for the parameter values to  be displayed it needs to be "DEF".

Another thing is that ones the parameter display value is changed , in the query it needs to be handled that the value should still be compared to "ABC" .

Please let me how to deal with this.

Thanks in advance.

- Namrata