The bakers at B’s Bakery would like to visualise all products to replenish in store so you will needto select a Left join. Once you have joined the data, go to a new worksheet and rename it StockLevel.In the data pane in Stock Level, right-click on the white space in Measures (red arrow location) andselect Create Calculated Field (circled). A new window will open up ready for calculating!1. Tableau will need a formula to calculate Stock Level. However, recall the null values that we haveearlier? Any rows with Null will be treated as missing data and Tableau ignores the entire row bydefault. We need to tell Tableau to treat Null as zero using the ZN() function as shown below. ZNmeans “Zero Null” and tests to see if a data entry is null, and if it is, it will return a value of zero.Now edit your calculation window to match the window below. Note to calculate the Stock Levelwe are computingStock LevelIremembering that ZN() will take care of those null values for us. Note that as you start typing theword Quantity or a café name autocomplete will help you out a little J Click OK when done.2. Now click on Data Source and you will find a new column with the calculated Stock Level (a fewrows of the Data grid shown below) with some entries negative and some positive – this is ok J3. We can now visualise the Stock Level for the bakers using a horizontal bar chart. In the Stock Levelworksheet drag Product (red circle below) into the rows shelf and Stock Level into the columnshelf. You can rearrange the chart in alphabetical order or sum level using the drop-down menu(green circle below).6. What conclusions can be drawn from the bar chart?7. If you would like to colour the bars based on the product items that require refilling, here’s acool coding trick J. Right-click on the white space in Dimensions where indicated below (redarrow)click on Create Calculated Field, then type the code as shown in the next image and click OK.You should now see a new Dimension called Stock Level (Colour) (below, red circle). Drag this newlycreated Dimension to the Marks card and drop it on Color and you’re done!(yours might be blue + orange – we edited our colours a little more J )
