Option 1: Convert the discrete field to a continuous numeric or date field

1. Select Analysis > Create Calculated Field
2. In the Calculated Field dialog box that opens, do the following, and then click OK:
   • Name the calculated field. In this example, the calculated field is named "Sales Bins"
   • In the formula field, create a calculation similar to the following:
   • (FLOOR([Sales]/1655)*1655)
     Note: The above calculation is the same calculation that Tableau Desktop uses to generate bins. 1655 is the size of the bin.
3. Right-click [Sales Bins] in the data pane and select Convert to Dimension
4. Right-click [Sales Bins] in the data pane and select Convert to Continuous
5. Replace [Sales (bins)] with [Sales Bins] on the Columns shelf
6. On the Marks card, change the mark type from Automatic to Bar in the dropdown menu
7. Add a reference line to the Sales Bin x-axis as normal. For detailed directions, see Reference Lines, Bands, Distributions, and Boxes
    

Option 2: Use a calculated field as a dual axis to mimic a reference line

1. Select Analysis > Create Calculated Field
2. In the Calculated Field dialog box that opens, do the following, and then click OK:
   • Name the calculated field. In this example, the calculated field is named "Mock Reference Line"
   • In the formula field, create a calculation similar to the following:
   • IF [Sub-Category]= "Chairs & Chairmats" OR [Sub-Category]= "Rubber Bands" THEN 1 END
3. Drag [Mock Reference Line] to the Rows shelf.
4. On the SUM(Mock... Marks card, do the following:
   • Change the mark type to Bar in the dropdown.
   • Click Size and adjust the width of the bars with the slider.
5. Right-click the [Mock Reference Line] y-axis in the view and select Edit Axis...
6. In the Edit Axis dialog, do the following and close the dialog:
   • For Range, select Fixed
   • Set the range from 0 to 1
7. Right-click [Mock Reference Line] on the Rows shelf and check Dual Axis.
8. Right-click [Mock Reference Line] on the Rows shelf and uncheck Show Header.