dynamic filter Axis change

[Kam1]

I have a dynamic filter (in filter Revenue and Transaction Quantity). When I choose revenue it should change Y Axis £0000 On the bar chart and when I choose Transaction Quantity it should change Y Axis 000 on the bar chart. How could I make this happen please. my code below

 parameter: choose_measure {
    type: unquoted
    allowed_value: {value:"net_amount" label:"Net Amount"}
    allowed_value: {value:"total_count" label:"Transaction Quantity"}

    default_value: "net_amount"
  }

  measure: dynamic_measure {
    type: number

    sql: 
        {% if choose_measure._parameter_value == 'net_amount' %}
              ${net_amount}
         {% elsif choose_measure._parameter_value == 'total_count' %}
              ${total_count}

         {% else %}
             ${net_amount}
        {% endif %} ;;
  }