2013錯誤查詢期間與MySQL服務器的連接丟失

Question

查詢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)

顯然，submission_id> = 0只有一條記錄。

查詢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

第三個問題是在我等待10分鍾之后

SELECT * from document WHERE state = 0 OR submission_id> = 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項應該是第一個，對嗎？

這是在我為“提交”列編制索引后發生的。 無論如何要刪除此列的索引？

供參考“描述文檔”看起來像

+---------------+--------------+------+-----+---------+----------------+
| 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

以下是刪除submission_id索引的方法

ALTER TABLE document DROP INDEX submission_id;

如果索引的名稱不是submission_id，則可以通過以下方式找到它：

SHOW CREATE TABLE document\G

您將看到表定義，其底部定義了索引。

您將看到索引的正確名稱。

查找submission_id索引名稱的另一種方法是：

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