SELECT
YEAR(dt) as the_year,
SUM(CASE WHEN MONTH(dt) = 1 THEN mc_gross ELSE 0 END) AS Total_Jan,
SUM(CASE WHEN MONTH(dt) = 2 THEN mc_gross ELSE 0 END) AS Total_Feb,
...
SUM(CASE WHEN MONTH(dt) = 12 THEN mc_gross ELSE 0 END) AS Total_Dec
FROM
transactions
GROUP BY
the_year;