Aggregate Operator: Count By Using Group Key

Overview                                                    

The Aggregate operator is used to count the number of entries in a data set. You can also use the operator’s Group Key field, which lets you to group the results into categories based on values from the original data.

For example, consider a Data Table component that stores the details of several dogs and their favorite foods. You'll configure a Data Workflow component to count how many dogs have the same favorite food. In this example , each type of food displays as a separate category using the Group Key field.

Configuration

Configure the Data Table Component

First, you'll add a Data Table component to store a list of dogs and favorite foods that your Data Workflow component can retrieve.

1. Drag and drop a Data Table component onto your canvas.

2. In the Property ID  and Label Text fields, enter dtDogs.

3. In the data table, enter the following:

   A	B
   name	favoriteFood
   Ivy	Peanut Butter
   Lucy	Beef Jerky
   Wally	Peanut Butter
   Nacho	Peanut Butter
   Thor	Salmon
   Holly	All Foods

   

4. Click Save & Close.

Configure the Data Workflow Component

Next, you'll add your Data Workflow component and bring your data into the Data Workflow using an Input operator. Then, you'll add an Aggregate operator to count how many dogs have the same favorite food. But to get an accurate count, you must count the names associated with each favorite food. So, you'll set the Aggregate operator to use the Value Key of name and Group Key of favoriteFood. Lastly, you'll view the result using a Console operator and the DevTools Console.

1. Drag and drop a Data Workflow component onto your canvas, placing it below your Data Table component.

2. In the Canvas Label Text and Property ID fields, enter dwfFavoriteFood.

Configure the Input Operator

1. Drag and drop an Input operator onto your Data Workflow canvas.

2. Configure the  operator's Info window as follows:

   Setting	Value
   Category	Input
   Component	dtDogs
   Required	Yes
   Source	Default

Configure the Aggregate Operator

1. Drag and drop an Aggregate operator onto your Data Workflow canvas.

2. Configure the  operator's Info window as follows:

   Setting	Value
   Category	Aggregate By
   Label	Favorite Food Counts
   Aggregation Type	Count By
   Join Group Keys	Yes
   Group Key	favoriteFood
   Value Key	name

3. Connect the output port (right) of the dtDogs Input operator to the input port (left) of the Favorite Food Counts Aggregate operator.

Configure the Console Operator

1. Drag and drop a Console operator onto your Data Workflow canvas.

2. Configure the  operator's Info window as follows:

   Setting	Value
   Category	Console
   Label	How many dogs have the same favorite food?

3. Connect the output port (right) of the Favorite Food Counts Aggregate operator to the input port (left) of the How many dogs have the same food? Console operator.

Here's how the completed workflow looks:

4. Click Save.

Configure the Button Component

Now, you'll add a Button component to  trigger the Data Workflow. Clicking the button executes the Data Workflow and counts the number of dogs who have the same favorite food.

1. Drag and drop a Button component onto your canvas, placing it below the Data Workflow component.

2. In the Property ID, enter btnFavoriteFood.

3. In the Label Text, enter Count Favorite Foods.

4. From the Action Type drop-down, select Event.

5. From the Trigger on Click drop-down, select dwfFavoriteFood.

   

6. Click Save.

7. Save your module.

Here's how your module looks in the Module Builder:

Preview your module in Express View and open the DevTools Console. Click the button to view the list of each favorite food for the dog type.