¿Cómo adaptarías esta consulta para obtener estadísticas de costo e impresión por supply_source (fuente de suministro)? SELECT device_type, operating_system, SUM(total_cost)/100000 AS total_cost_dollars, ((SUM(total_cost)/100000)/SUM(impressions))*1000 AS avg_cpm, SUM(impressions) AS impressions FROM dsp_impressions GROUP BY 1,2

The correct answer modifies the original query to group by supplysource instead of devicetype and operatingsystem. The SELECT statement is updated to include supplysource as the primary dimension, and the GROUP BY clause is changed to GROUP BY 1 to aggregate results solely by the first selected column, supplysource. The calculations for totalcostdollars, avgcpm, and impressions remain the same as they correctly calculate the desired metrics. The first incorrect option includes GROUP BY 1,2, which would group by supplysource and an undefined second column, leading to an error or unexpected results. The second incorrect option uses dspinventory instead of dspimpressions as the source table, which may not contain the necessary impression data, and also incorrectly divides totalcost by 100,000,000 instead of 100,000.