随机取记录问题

select top 5 * from tb where 条件 order by newid()

SELECT * FROM table_name ORDER BY rand() LIMIT 5;

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mysql> use test1;
Database changed
mysql> SELECT * FROM user ORDER BY rand() LIMIT 5;
+------+------+
| id   | name |
+------+------+
|    2 | joe  |
|    5 | ggg  |
|    6 | vvcc |
|    6 | vvvv |
| NULL | cccc |
+------+------+
5 rows in set (0.00 sec)

mysql>