# 在 UPDATE 里使用 ORDER BY 和 LIMIT 

__*LIMIT 子句*__

```
tidb> SELECT * FROM test.r1;
+----+------+
| id | name |
+----+------+
|  1 | Z    |
|  2 | C    |
+----+------+
2 rows in set (0.01 sec)

tidb> UPDATE test.r1 SET name='Z' WHERE id < 10 ~!@ORDER BY id DESC@!~ LIMIT 1;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

tidb> SELECT * FROM test.r1;
+----+------+
| id | name |
+----+------+
|  1 | Z    |
|  2 | ~!@Z@!~    |
+----+------+
2 rows in set (0.00 sec)
```
-------------------------------------------------

就像 SELECT 一样,你必须使用 ORDER BY 来确保表行的顺序。