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MySQL CREATE statement with KEY keyword
As stated in the official docs −
KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can also be specified as just KEY when given in a column definition. This was implemented for compatibility with other database systems.
Let us first create a table −
mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(50), Age int ); Query OK, 0 rows affected (0.69 sec)
Following is the query for INDEX, which is a synonym to KEY −
mysql> create index Name_Age_Index on DemoTable(Name,Age); Query OK, 0 rows affected (0.65 sec) Records: 0 Duplicates: 0 Warnings: 0
Let us check the description of the table once again −
mysql> desc DemoTable;
This will produce the following output −
+-------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+----------------+ | Id | int(11) | NO | PRI | NULL | auto_increment | | Name | varchar(50) | YES | MUL | NULL | | | Age | int(11) | YES | | NULL | | +-------+-------------+------+-----+---------+----------------+ 3 rows in set (0.01 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable(Name,Age) values('Robert',21);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable(Name,Age) values('Bob',23);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable(Name,Age) values('David',22);
Query OK, 1 row affected (0.39 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+----+--------+------+ | Id | Name | Age | +----+--------+------+ | 2 | Bob | 23 | | 3 | David | 22 | | 1 | Robert | 21 | +----+--------+------+ 3 rows in set (0.00 sec)
Updated on: 01-Oct-2019
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