Syntax error What does the KEY keyword mean in MySQL?

What does the KEY keyword mean in MySQL?

Key is synonymous to an index. If you want to create an index for a column, then use ?Key'.

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.

The key can be used with Primary Key:

Let us first create a table. Here is the query to set primary key for a column "id".

mysql> create table KeyDemo
    -> (
    -> id int,
    -> primary key(id)
    -> );
Query OK, 0 rows affected (0.55 sec)

Inserting two records.

mysql> insert into KeyDemo values(1);
Query OK, 1 row affected (0.12 sec)

mysql> insert into KeyDemo values(2);
Query OK, 1 row affected (0.14 sec)

To display all the records.

mysql> select *from KeyDemo;

Here is the output.

+----+
| id |
+----+
|  1 |
|  2 |
+----+
2 rows in set (0.00 sec)
Updated on: 2019-07-30T22:30:23+05:30

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