mysql 选出前五个元素

mysql> select * from test;
+----+----------+-------+-----------+
| id | name     | score | subject   |
+----+----------+-------+-----------+
|   | xiaoming |     | shuxue    |
|   | xiaohong |     | shuxue    |
|   | xiaohong |     | english   |
|   | xiaohong |     | physics   |
|   | xiaohong |     | astronaut |
|   | xiaoming |     | physics   |
|   | xiaoming |     | astronaut |
|   | xiaoming |     | english   |
|   | xiaobai  |     | astronaut |
|  | xiaobai  |     | english   |
|  | xiaobai  |     | physics   |
|  | xiaobai  |     | shuxue    |
|  | xiaohei  |     | astronaut |
|  | xiaohei  |     | shuxue    |
|  | xiaohei  |     | physics   |
|  | xiaohei  |     | english   |
+----+----------+-------+-----------+
 rows in set (0.00 sec)

mysql> select * from test where id between  and ;
+----+----------+-------+-----------+
| id | name     | score | subject   |
+----+----------+-------+-----------+
|   | xiaoming |     | shuxue    |
|   | xiaohong |     | shuxue    |
|   | xiaohong |     | english   |
|   | xiaohong |     | physics   |
|   | xiaohong |     | astronaut |
+----+----------+-------+-----------+
 rows in set (0.00 sec)

mysql> select * from test where id <=;
+----+----------+-------+-----------+
| id | name     | score | subject   |
+----+----------+-------+-----------+
|   | xiaoming |     | shuxue    |
|   | xiaohong |     | shuxue    |
|   | xiaohong |     | english   |
|   | xiaohong |     | physics   |
|   | xiaohong |     | astronaut |
+----+----------+-------+-----------+
 rows in set (0.00 sec)

mysql> select * from test where id in (,,,,);
+----+----------+-------+-----------+
| id | name     | score | subject   |
+----+----------+-------+-----------+
|   | xiaoming |     | shuxue    |
|   | xiaohong |     | shuxue    |
|   | xiaohong |     | english   |
|   | xiaohong |     | physics   |
|   | xiaohong |     | astronaut |
+----+----------+-------+-----------+
 rows in set (0.00 sec)