如何刪除mysql中列的鍵約束？

Question

如何刪除列鍵在MySQL？（主鍵，外，獨特的全）

這裏我給出主鍵列ID

ALTER TABLE table ADD PRIMARY KEY(id); 

現在我要刪除它，並沒有任何鍵列ID 是有使用任何way.i，

ALTER TABLE `table` MODIFY `id` INT 

但它實際上給UNIQUE鍵

Answer 1

您可以使用

ALTER TABLE `table` MODIFY `id` INT ; 
ALTER TABLE `table` DROP PRIMARY KEY; 

Answer 2

嗨，你可以運行下面的命令：

ALTER TABLE tableName修改列ID INT，DROP PRIMARY KEY;

mysql> desc TestTable; 
 

 
+-------+-------------+------+-----+---------+-------+ 
 
| Field | Type  | Null | Key | Default | Extra | 
 
+-------+-------------+------+-----+---------+-------+ 
 
| id | int(10)  | NO | PRI | NULL |  | 
 
| name | varchar(30) | NO |  | NULL |  | 
 
+-------+-------------+------+-----+---------+-------+ 
 
2 rows in set (0.05 sec) 
 

 
mysql> ALTER TABLE TestTable MODIFY COLUMN id INT(10),DROP PRIMARY KEY; 
 
Query OK, 0 rows affected (0.62 sec) 
 
Records: 0 Duplicates: 0 Warnings: 0 
 

 
mysql> desc TestTable; 
 
+-------+-------------+------+-----+---------+-------+ 
 
| Field | Type  | Null | Key | Default | Extra | 
 
+-------+-------------+------+-----+---------+-------+ 
 
| id | int(10)  | YES |  | NULL |  | 
 
| name | varchar(30) | NO |  | NULL |  | 
 
+-------+-------------+------+-----+---------+-------+ 
 
2 rows in set (0.00 sec)