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How do I drop a primary key in MySQL?
To drop a primary key, use ALTER at first to alter the table. With that, use DROP to drop the key as in the below
Syntax
alter table yourTableName drop primary key;
Let us first create a table −
mysql> create table DemoTable -> ( -> StudentId int NOT NULL, -> StudentName varchar(20), -> StudentAge int, -> primary key(StudentId) -> ); Query OK, 0 rows affected (0.48 sec)
Here is the query to check the description of table −
mysql> desc DemoTable;
This will produce the following output−
+-------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------+-------------+------+-----+---------+-------+ | StudentId | int(11) | NO | PRI | NULL | | | StudentName | varchar(20) | YES | | NULL | | | StudentAge | int(11) | YES | | NULL | | +-------------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec)
Following is the query to drop a primary key in MySQL −
mysql> alter table DemoTable drop primary key; Query OK, 0 rows affected (1.70 sec) Records: 0 Duplicates: 0 Warnings: 0
Let us check the table description once again −
mysql> desc DemoTable;
This will produce the following output −
+-------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------+-------------+------+-----+---------+-------+ | StudentId | int(11) | NO | | NULL | | | StudentName | varchar(20) | YES | | NULL | | | StudentAge | int(11) | YES | | NULL | | +-------------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec)
Updated on: 18-Dec-2019
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