레스토랑 웨이터의 팁 분석 : sovlesql

난이도 : 2

answer

SELECT  day, time, 
        ROUND(AVG(tip),2) as avg_tip, 
        ROUND(AVG(size),2) as avg_size
FROM    tips
GROUP BY
        day, time
ORDER BY  
        day ASC, time ASC