Question

查询1是

SELECT id,state,submission_id FROM document WHERE submission_id>=0;

+---------+-------+---------------+
| id      | state | submission_id |
+---------+-------+---------------+
| 3000001 |    -1 |         12345 | 
+---------+-------+---------------+
1 row in set (0.00 sec)

显然，只有一条记录提交了submission_id＆gt; = 0。

查询2是

SELECT id,state,submission_id FROM document WHERE submission_id>=0 OR state=0 ORDER BY submission_id LIMIT 5;

ERROR 2013 (HY000): Lost connection to MySQL server during query

第三个问题是在我等待10分钟之后

SELECT * from document WHERE state = 0 OR submission_id＆gt; = 0 order by submission_id desc limit 5;

+----+-------+---------------+
| id | state | submission_id |
+----+-------+---------------+
|  1 |     1 |            -1 | 
|  2 |     1 |            -1 | 
|  3 |     1 |            -1 | 
|  4 |     1 |            -1 | 
|  5 |     1 |            -1 | 
+----+-------+---------------+

怎么了？ id = 3000001项应该是第一个，对吗？

在我为“提交”列编制索引后会发生这种情况。无论如何要删除此列的索引？

供参考“描述文件”看起来像

+---------------+--------------+------+-----+---------+----------------+
| Field         | Type         | Null | Key | Default | Extra          |
+---------------+--------------+------+-----+---------+----------------+
| id            | int(11)      | NO   | PRI | NULL    | auto_increment | 
| state         | int(11)      | YES  | MUL | NULL    |                | 
| submission_id | int(11)      | YES  | MUL | NULL    |                | 
+---------------+--------------+------+-----+---------+----------------+

Answer 1

以下是删除submission_id索引的方法

ALTER TABLE document DROP INDEX submission_id;

如果索引的名称不是submission_id，则可以通过以下方式找到它：

SHOW CREATE TABLE document\G

您将看到底部定义了索引的表定义。

您将看到索引的正确名称。

查找submission_id索引名称的另一种方法是：

SELECT index_name FROM information_schema.statistics
WHERE table_name='document'
AND column_name='submission_id';

2013错误查询期间与MySQL服务器的连接丢失

1 个答案: