yii2 debug database panal 求解 [ 求助交流 ]

yii2 debug database panal [-] Explain select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE * ALL ** NULL NULL NULL 354 Using where; Using temporary; Using filesort 1 SIMPLE * ALL NULL NULL NULL NULL 3372 Using where; Using join buffer (Block Nested Loop) 1 SIMPLE *** ALL NULL NULL NULL NULL 1498 Using where; Using join buffer (Block Nested Loop)

求解这几个是什么意思呢