有時候我們需要資料庫中的實時資料，而這些實時資料又是插入在表最後面的，所以我們需要獲取表中最後面的幾條記錄，怎麼操作呢

select * from msg order by id desc limit n ;

那獲取資料表中總共有多少條記錄呢

select count(*) from msg;

結果如下

mysql> select * from msg order by id desc limit 2 ;
+-----+-------------+--------------+------------+------------+----+-----------+------------+----+-----------+-------+
| id  | terminal_id | msg_time     | gps_status | degree_lon | m1 | s1        | degree_lat | m2 | s2        | speed |
+-----+-------------+--------------+------------+------------+----+-----------+------------+----+-----------+-------+
| 339 | 66666       | 140523093712 | A1         | +113       | 14 | 584765632 | +23        | 5  | 542285184 |     0 |
| 338 | 99999       | 140523093755 | A          | 113        | 55 | 179296880 | 22         | 34 | 86865232  | 50.32 |
+-----+-------------+--------------+------------+------------+----+-----------+------------+----+-----------+-------+
2 rows in set

mysql> select count(*) from msg;
+----------+
| count(*) |
+----------+
|      339 |
+----------+
1 row in set

mysql>