View the original community article here

Last tested: Sep 6, 2019
 

The Problem

Quite frequently, a sea of values need to be displayed in a visualization to capture the whole story, such as company growth over time and how different products compare to one another. Sometimes, to answer a specific question, a particular value needs to stand out from the rest. If the value is static, we can always use the filter parameter in the LookML; however, if we want the users to be able to edit the filter to their particular question, we need to use a parameter and a duplicate field.

The Solution

The process is a variation of our doc on using Liquid Parameters

1. Create a parameter in the view. https://docs.looker.com/reference/field-params/parameter
   1. The parameter will function if allowed_value is not added.
   2. If the user still wants to auto-populate the parameter, but has a massive amount of allowed values, they can instead use the suggest_dimension parameter to achieve the same functionality.
   3. Warning: If you will be working in an explore where this view is not the base view, you will also need to add the suggest_explore parameter referencing an explore where this is the base view.
      Why are filter suggestions not populating?
2. Create a duplicate field (in this example a dimension) that will return the value entered in the parameter or a null value.
   1. In the sql statement, create a CASE statement referencing the parameter.
      sql: CASE

WHEN ${original_field} = {% parameter name_of_parameter %} THEN {original_field}

ELSE null

END ;;
      1. The ELSE value can also be something generic such as "Other Values"
   2. Warning: If your original field has the link parameter, this CASE statement will get a bit wonky. In that case, reference the original column in the source table.
       
3. Add the parameter and new field to your Explore query/tile edit modal.
4. Pivot on the duplicated dimension.
5. If applicable to your visualization (ex: scatterplot, line vis), in the Visualization Edit modal, turn off "Plot Null Values"
6. Edit the visualization as desired!
   1. Define color values for your series in the customization section.
   2. If you used the "ELSE null", customize the series to display the preferred name.