The Best Of Baseball Awards

SELECT 
	SUM(salary), 
	teams.name, 
	salaries.yearid 
FROM salaries
LEFT JOIN teams 
	ON teams.teamid = salaries.teamid 
	AND teams.yearid = salaries.yearid
GROUP BY 
	teams.name, 
	salaries.yearid
ORDER BY
	SUM(salary) 
	DESC;

Hey guys, noob question. Why do I have to left join on both team id and year id? Wouldn’t teamid already return matching columns. I know I have to because the result is different when I only run one, but I just want to see what I’m missing…