We have a case where a multi-select field has one value of 'Other' in the dropdown list. If 'Other' appears in the list, another field that is marked as required is cleared. If 'Other' is not in the list, the other field is populated with the string 'N/A'.
The rule to do this is executed for any value of the first field. The SQL is:
select decode(instr('[REQD.VP.FIELD1]','Other'),0,'N/A',''), decode(instr('[REQD.VP.FIELD1]','Other'),0,'N/A','') from dual
The result value 'N/A' or Null will be placed in the Result Field. The statement is duplicated in order to fill both the visible and hidden parameters.
If you want the result field to be populated with a particular value the given SQL will work, with minor edits (Replace the field token, search string and results). If you want the result field modified in another way you may need another solution.
Feel free to expand on how you would like the result field modified.
We are using this in 7.5 SP7 in a rule with a single dependency on a multi-select enabled field (contains any value). The option to add the dependency works normally and all of the options for dependency types are available. It is just tricky to look for a specific value in the list.