下面的sql为什么报错select flag event sumcase event when item_to_gold then price else -price FROM_UNIXTIMEcreate_time Y-m-d as datefrom vp_user_inventory_history ih join vp_user_inventory_history_item hi

这段SQL语句报错的原因是因为SELECT语句中SUM函数的语法错误。应该将SUM函数的参数放在括号内，修改后的SQL语句如下：

SELECT flag, event, SUM(CASE event WHEN item_to_gold THEN price ELSE -price END), FROM_UNIXTIME(create_time, '%Y-%m-%d') AS date FROM vp_user_inventory_history ih JOIN vp_user_inventory_history_item hi ON ih.id = hi.history_id WHERE user_id != 94 AND user_id > 0 GROUP BY date, flag ORDER BY date DESC;