I have a form which has multi select field.(drop down box allowing multiple sele

I have a form which has multi select field.(drop down box allowing multiple select).
In the field i am populating a list of countries, fetched from the DB. The DB table has anothr column riskVal against each country.
Now when i multiselect the countries in the form, i need to get the associted riskVal values. i ,e if the user selects 5 countries, i need to get the 5 riskVal associated to the country. Actual req is sum of all the selected countries risk.
My query rule is already fetchin all the data for both columns. I need suggestion on how to get the values in this case....

OriginalPostID-61702

OriginalPostID-61702