报错信息:
Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column xxxx which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_modeonly_full_group_by
原因:
这…
对象头 Mark word 标记字段 用于存储对象自身的运行时数据,如哈希码(HashCode)、GC分代年龄、锁状态标志、线程持有的锁、偏向线程ID、偏向时间戳等 ClassPoint 类型指针 对象指向它的类型元数据的指针,Java虚拟机通过这个指针 来…