7
这是我正在研究的查询之一的mysql解释计划。mysql解释输出中语句顺序的意义是什么?
+----+-------------+--------+-------+---------------+---------+---------+------+------+-------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+--------+-------+---------------+---------+---------+------+------+-------+
| 1 | SIMPLE | table2 | index | NULL | PRIMARY | 4 | NULL | 6 | |
| 1 | SIMPLE | table3 | ALL | NULL | NULL | NULL | NULL | 23 | |
| 1 | SIMPLE | table1 | ALL | NULL | NULL | NULL | NULL | 8 | |
| 1 | SIMPLE | table5 | index | NULL | PRIMARY | 4 | NULL | 1 | |
+----+-------------+--------+-------+---------------+---------+---------+------+------+-------+
4行集(0秒)
什么是这个输出语句的顺序的意义是什么? 这是否意味着table5在所有其他人之前被读取?