Aggregating data

An aggregation operation can often be thought of as summing some data items, but the Studio also uses aggregating functions to work out counts, minimum and maximum values, and average values, amongst other things. We will look at a simple data summation example.

The file we will work with is in the resources directory of this chapter and is named invoices.csv. It shows a number of invoices with the invoice number, customer name, and invoice amount. We want to extract the sum of the invoices for each customer.

1. Create a new job and name it Aggregating.

2. Create a File delimited metadata item for the invoices.csv file, following the steps we have used previously. Name column 0 as invoice_number, column 1 as customer_name, and column 2 as invoice_value. The Studio will choose a data type of float for the invoice value. It is better to use the data type BigDecimal, which preserves the two decimal places we expect with monetary values, so change this in the Type column of the final...