Use dimension when creating measure with Case

[miguelposada]

I am trying to create a measure conditionally based on a dimension.

column is a dimension while geo_area.count_anon and count_anon are measures of sum type.

This measure is not working well.

  measure:measure_count_lvl3 {
    type: number
    sql:
      CASE
      WHEN  ${column}='GEO_AREA_ID' THEN ${geo_area.count_anon}
      ELSE ${count_anon}
    END ;;
  }

The error:

What can I do to solve this?