日志
MySQL中关于update,delete语句的limite用法
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语法：
DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]
UPDATE [LOW_PRIORITY] [IGNORE] table_reference
SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]
例子：
mysql> select * from kider;
+----+--------------------------------------+
| id | v_str |
+----+--------------------------------------+
| 1 | 5317c160-9daa-11de-ba34-00188be50907 |
| 2 | 574bc150-9daa-11de-ba34-00188be50907 |
| 3 | 5d22a0b2-9daa-11de-ba34-00188be50907 |
| 4 | 5d22a2ec-9daa-11de-ba34-00188be50907 |
| 5 | 607bff06-9daa-11de-ba34-00188be50907 |
| 6 | 607c00fa-9daa-11de-ba34-00188be50907 |
| 7 | 607c0154-9daa-11de-ba34-00188be50907 |
| 8 | 607c0190-9daa-11de-ba34-00188be50907 |
+----+--------------------------------------+
8 rows in set (0.00 sec)
mysql> delete from kider limit 2;
Query OK, 2 rows affected (0.00 sec)
mysql> select * from kider;
+----+--------------------------------------+
| id | v_str |
+----+--------------------------------------+
| 3 | 5d22a0b2-9daa-11de-ba34-00188be50907 |
| 4 | 5d22a2ec-9daa-11de-ba34-00188be50907 |
| 5 | 607bff06-9daa-11de-ba34-00188be50907 |
| 6 | 607c00fa-9daa-11de-ba34-00188be50907 |
| 7 | 607c0154-9daa-11de-ba34-00188be50907 |
| 8 | 607c0190-9daa-11de-ba34-00188be50907 |
+----+--------------------------------------+
6 rows in set (0.01 sec)
mysql> delete from kider order by id limit 2;
Query OK, 2 rows affected (0.01 sec)
mysql> select * from kider;
+----+--------------------------------------+
| id | v_str |
+----+--------------------------------------+
| 5 | 607bff06-9daa-11de-ba34-00188be50907 |
| 6 | 607c00fa-9daa-11de-ba34-00188be50907 |
| 7 | 607c0154-9daa-11de-ba34-00188be50907 |
| 8 | 607c0190-9daa-11de-ba34-00188be50907 |
+----+--------------------------------------+
4 rows in set (0.00 sec)
mysql> select * from kider;
+----+--------------------------------------+
| id | v_str |
+----+--------------------------------------+
| 5 | 607bff06-9daa-11de-ba34-00188be50907 |
| 6 | 607c00fa-9daa-11de-ba34-00188be50907 |
| 7 | 607c0154-9daa-11de-ba34-00188be50907 |
| 8 | 607c0190-9daa-11de-ba34-00188be50907 |
+----+--------------------------------------+
4 rows in set (0.00 sec)
mysql> update kider set v_str= concat( v_str,' + update') order by id limit 2;
Query OK, 2 rows affected (0.01 sec)
Rows matched: 2 Changed: 2 Warnings: 0
mysql> select * from kider;
+----+-----------------------------------------------+
| id | v_str |
+----+-----------------------------------------------+
| 5 | 607bff06-9daa-11de-ba34-00188be50907 + update |
| 6 | 607c00fa-9daa-11de-ba34-00188be50907 + update |
| 7 | 607c0154-9daa-11de-ba34-00188be50907 |
| 8 | 607c0190-9daa-11de-ba34-00188be50907 |
+----+-----------------------------------------------+
4 rows in set (0.00 sec)
mysql> update kider set v_str= concat( v_str,' + update') limit 2;
Query OK, 2 rows affected (0.00 sec)
Rows matched: 2 Changed: 2 Warnings: 0
mysql> select * from kider;
+----+--------------------------------------------------------+
| id | v_str |
+----+--------------------------------------------------------+
| 5 | 607bff06-9daa-11de-ba34-00188be50907 + update + update |
| 6 | 607c00fa-9daa-11de-ba34-00188be50907 + update + update |
| 7 | 607c0154-9daa-11de-ba34-00188be50907 |
| 8 | 607c0190-9daa-11de-ba34-00188be50907 |
+----+--------------------------------------------------------+
4 rows in set (0.00 sec)
