"Must provide a field name for parameter" error message

[nikitanaresh]

Hi, I’m trying to create a simple parameter to choose between 2 dimensions to breakdown a view. I’ve copied the syntax exactly from the Looker docs, but keep getting an error saying that the “parameter’ needs a field name:

parameter: regiondrilldown {
    type: unquoted
    allowed_value: {value: "Country"}
    allowed_value: {value: "State"}
    allowed_value: {value: "City"}
  }

  dimension: geo_breakdown {
    type: string
    label_from_parameter: regiondrilldown
    sql:
      case
        when {% parameter ${regiondrilldown} %} = 'Country' Then ${country}
        when {% parameter ${regiondrilldown} %} = 'State' then ${state}
        when {% parameter ${regiondrilldown} %} = 'City' then ${city}
      end ;;
  }

[Dawid]

What if you simplify it this way, provided that your table dimensions are called like that

dimension: geo_breakdown {
    type: string
    label_from_parameter: regiondrilldown
    sql: ${TABLE}.{% parameter regiondrilldown %} ;;
  }

That’s because you can’t do

${{% parameter regiondrilldown %}}

[nikitanaresh]

Tried that, but I’m still getting the same field name error. 

I’m trying this out on the Qwiklabs ecommerce model. Could it just be an issue with the testing environment?

[Dawid]

If you keep the code as you have then you can’t have parameter unquoted as it will produce

Country = "Country"

Unquoted means the value is entered as is and not as string literal

[n_davis · Accepted solution]

I usually do parameters this way @nikitanaresh 

parameter: regiondrilldown {
    type: unquoted
    allowed_value: {value: "country" 
                    label: "Country"}
    allowed_value: {value: "state"}
                    label: "State"}
    allowed_value: {value: "city"}
                    label: "City"}
  }

  dimension: geo_breakdown {
    type: string
    label_from_parameter: regiondrilldown
    sql:
        {% if regiondrilldown._parameter_value == 'country' %} ${country}
        {% elsif regiondrilldown._parameter_value == 'state' %} ${state}
        {% elsif regiondrilldown._parameter_value == 'city' %} ${city}
        {% else %} ${country}
        {% endif %};;
  }

[Dawid]

The above is better because the conditional logic is within Liquid, so parameter can be unquoted but you make the paramter’s output to be used in conditional logic in SQL

[nikitanaresh]

This works! I guess I just had my quotes and = vs == mixed up.

I fixed that and it ran with both an if and a case statement.