found an interesting problem with timestamp after the mysql5.6 version, as follows:
mysql> desc test_idx;
+--------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(255) | NO | | NULL | |
| sid | int(11) | NO | UNI | NULL | |
| time_1 | timestamp(6) | YES | | NULL | |
| time_2 | timestamp(2) | YES | | NULL | |
| time_3 | timestamp(4) | YES | | NULL | |
| time_4 | timestamp | YES | | NULL | |
+--------+--------------+------+-----+---------+----------------+
7 rows in set (0.00 sec)
mysql> select * from test_idx;
+----+------+-----+----------------------------+------------------------+--------------------------+---------------------+
| id | name | sid | time_1 | time_2 | time_3 | time_4 |
+----+------+-----+----------------------------+------------------------+--------------------------+---------------------+
| 2 | zhao | 1 | 2018-09-20 20:39:59.000000 | 2018-09-20 20:40:05.00 | 2018-09-20 20:40:09.0000 | 2018-09-20 20:40:55 |
+----+------+-----+----------------------------+------------------------+--------------------------+---------------------+
1 row in set (0.00 sec)problem description: when the length of timestamp is specified when the table is created (the maximum is 6), timestamp can keep the last 6 decimal places, which are described as microseconds according to the official document.
question: does it mean that after 5. 6, timestamp is accurate to microseconds, and then timestamp occupies 4 bytes, so how does the bottom store these 6 decimal places?
