SELECT p.player_id,username,current_level, CASE WHEN current_level>=30 THEN "高阶玩家" ELSE "新秀玩家" END AS player_category,ROUND(SUM(cost),2) AS total_april_spending FROM ( SELECT player_id,username,level AS current_level FROM players WHERE MONTH(creation_date)=3 AND YEAR(creation_...
