Let's practice! - Aggregating Data

• Obtain a grand total of the demand_loss_mw column by using the SUM function, and alias the result as MRO_demand_loss.

• SELECT .......... AS .......... FROM grid;

• Fill in the blank

• Only retrieve rows WHERE demand_loss_mw is not NULL and nerc_region is 'MRO'.

• SELECT SUM(demand_loss_mw) AS MRO_demand_loss FROM grid

• WHERE ______;

• Return the COUNT of the grid_id column, aliasing the result as grid_total.

• SELECT ........ AS ........ FROM grid;

• Make the count more meaningful by restricting it to records where the nerc_region is 'RFC'. Name the result RFC_count.

• SELECT COUNT(grid_id) AS .......... FROM grid WHERE ..........;

• Find the minimum value from the affected_customers column, but only for rows where demand_loss_mw has a value. Name the result min_affected_customers.

• SELECT

  MIN(affected_customers) AS min_affected_customers

  FROM grid

  WHERE demand_loss_mw IS NOT NULL;

• SELECT

  MIN(affected_customers) AS min_affected_customers

  FROM grid

  WHERE demand_loss_mw NOT NULL;

• SELECT

  MIN(affected_customers) AS min_affected_customers

  FROM grid

  WHERE demand_loss_mw IS NULL;

• SELECT

  MIN(affected_customers) AS min_affected_customers

  FROM grid

  WHERE demand_loss_mw == NULL;

• Find the maximum value from the affected_customers column, but only for rows where demand_loss_mw has a value. Name the result max_affected_customers.

• SELECT

  MAX(affected_customers) AS max_affected_customers

  FROM grid

  WHERE demand_loss_mw IS NULL;

• SELECT

  MAX(affected_customers) AS max_affected_customers

  FROM grid

  WHERE demand_loss_mw NOT NULL;

• SELECT

  MAX(affected_customers) AS max_affected_customers

  FROM grid

  WHERE demand_loss_mw IS NOT NULL;

• SELECT

  MAX(affected_customers) AS max_affected_customers

  FROM grid

  WHERE demand_loss_mw == NULL;