Data Aggregation

Aggregation functions are used to aggregate your data. For instance, consider a scenario, where you have a huge Sales data in tabular format. Now, if you want the total sales or an average sale from a tabular sales data you need to apply aggregation function to get the desired data.

When you apply `Aggragation` to a DataModel, it transforms it and creates a new DataModel.

Aggregation functions can be applied to n number of fields of the DataModel which generates a new DataModel with the resultant data.

The supported aggregation functions are listed below:

• SUM
• COUNT
• AVERAGE
• MAX
• MIN

In this article, we will apply all the above operations and check the result based on the tabular data shown below:

Order Date Country Sales Quantity Shipping Cost
1/22/2011 Australia 59.724 6 27.43
1/22/2011 United States 125.248 3 3.64
1/22/2011 Australia 6.318 1 1.77
1/24/2011 South Africa 110.808 3 9.92
1/24/2011 China 40.08 6 4.31
1/24/2011 India 59.25 4 4.27
1/24/2011 United States 5.94 3 0.95
1/26/2011 Japan 79.38 3 13.82
1/26/2011 India 342.51 7 13.22

SUM

SUM is a function which can be used when you have a list of numeric data and you want to calculate the sum of it. In the above tabular data, to calculate the sum of the values in Sales column, set the SUM function as shown in the code below:

``````Aggregation aggregateSum = new Aggregation {
"Sales", Aggregation.Function.SUM
};
DataModel totalSum = model.Aggregate(aggregateSum);``````

In the above code:

• Aggregation is a class.
• aggregateSum is an object which holds information of the data to be aggregated.
• Sales is the column name on which the aggregation function will be applied.
• In `Aggregation.Function.SUM`, Function is an enum of Aggregation class which specifies the function to be applied on the data.
• DataModel is a class.
• totalSum is the object which holds the resultant data.

The output after running the above code looks like:

Sales
829.258

COUNT

COUNT is a function which can be used when you want to count the number of rows of a column in the DataModel.

The code to apply the COUNT function is shown below:

``````Aggregation aggregateCount = new Aggregation {
"Country", Aggregation.Function.COUNT
};
DataModel noOfCountry = model.Aggregate(aggregateCount);``````

In the above code:

• Aggregation is a class.
• aggregateCount is an object which holds information of the data to be aggregated.
• Country is the column name on which the aggregation function will be applied.
• In `Aggregation.Function.COUNT`, Function is an enum of Aggregation class which specifies the function to be applied on the data.
• DataModel is a class.
• noOfCountry is the object which holds the resultant data.

The output after running the above code looks like:

Country
9

Average

AVERAGE is a function which can be used when you have a list of numeric data and you want to calculate the average of it. In the above tabular data, to calculate the average of the values in Quantity column, set the AVERAGE function as shown in the code below:

``````Aggregation aggregateAverage = new Aggregation {
"Quantity", Aggregation.Function.AVERAGE
};
DataModel finalAverage = model.Aggregate(aggregateAverage);``````

In the above code:

• Aggregation is a class.
• aggregateAverage is an object which holds information of the data to be aggregated.
• Quantity is the column name on which the aggregation function will be applied.
• In `Aggregation.Function.AVERAGE`, Function is an enum of Aggregation class which specifies the function to be applied on the data.
• DataModel is a class.
• finalAverage is the object which holds the resultant data.

The output after running the above code looks like:

Sales
4

MAX

MAX is a function which can be used when you have a list of numeric data and you want the largest value of the list. In the above tabular data, if you want the largest Sales value, set the MAX function as shown in the code below:

``````Aggregation aggregateMax = new Aggregation {
"Sales", Aggregation.Function.MAX
};
DataModel maxValue = model.Aggregate(aggregateMax);``````

In the above code:

• Aggregation is a class.
• aggregateMax is an object which holds information of the data to be aggregated.
• Sales is the column name on which the aggregation function will be applied.
• In `Aggregation.Function.MAX`, Function is an enum of Aggregation class which specifies the function to be applied on the data.
• DataModel is a class.
• maxValue is the object which holds the resultant data.

The output after running the above code looks like:

Sales
342.51

Min

MIN is a function which can be used when you have a list of numeric data and you want the lowest value of the list. In the above tabular data, if you want the lowest Sales value, set the MIN function as shown in the code below:

``````Aggregation aggregateMin = new Aggregation {
"Sales", Aggregation.Function.MIN
};
DataModel minValue = model.Aggregate(aggregateMin);``````

In the above code:

• Aggregation is a class.
• aggregateMin is an object which holds information of the data to be aggregated.
• Sales is the column name on which the aggregation function will be applied.
• In `Aggregation.Function.MIN`, Function is an enum of Aggregation class which specifies the function to be applied on the data.
• DataModel is a class.
• minValue is the object which holds the resultant data.

The output after running the above code looks like:

Sales
5.94