Exercise

Summing

Summing and counting are key ways of aggregating data, regardless of whether you are using a database, manipulating a spreadsheet, or using a programming language such as Python or R. Let's see how to do it in T-SQL using the grid table from Chapter 1.

You'll start by obtaining overall sums, focusing specifically on the 'MRO' region.

nerc_region map

Instructions

100 XP

Obtain a grand total of the demand_loss_mw column by using the SUM function, and alias the result as MRO_demand_loss.
Only retrieve rows WHERE demand_loss_mw is not NULL and nerc_region is 'MRO'.