How to set a token when the field exists?

[timgren]

I'm looking for a way to set a token when the column exists (regardless of value).  
Tried these with no luck. 

<eval token=if(isnotnull($row.MyCol$),useValue=$row.MyCol$,null())>
<eval token=case($row.MyCol$ != &quot;&quot; , useValue=$row.MyCol$) 

Thoughts? 

[kamlesh_vaghela]

@timgren 

You can also put logic in your search and display only the required columns by adding

| eval flag=if(isnull(MyCol),"0","1")
| eval flag_value=if(isnull(MyCol) AND MyCol!="" ,null(),MyCol)

and you can manage your tokens in drill down like this.

<drilldown>
          <condition match="$row.flag$=&quot;1&quot;">
            <set token="useValue">$row.flag_value$</set>
          </condition>
          <condition>
            <unset token="useValue" />
          </condition>
        </drilldown>

I hope this will help you.

Thanks
KV
If any of my replies help you to solve the problem Or gain knowledge, an upvote would be appreciated.

[richgalloway]

Have you tried this?

<eval token=if(isnotnull($row.MyCol$), $row.MyCol$, null())>

[timgren · Accepted solution]

Not quite, but that led me to one that does. 
<eval token="MyCol">if(isnotnull($row.MyCol$),"UseValue=".$row.MyCol$,"")</eval> 

Thanks!