在MySQL中的创建表上创建索引？
让我们首先创建一个表和索引-
mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(20), StudentAge int, StudentCountryName varchar(100), INDEX first_Name_index(StudentFirstName) );
检查表的描述-
mysql> desc DemoTable;
这将产生以下输出-
+--------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------------+--------------+------+-----+---------+----------------+ | StudentId | int(11) | NO | PRI | NULL | auto_increment | | StudentFirstName | varchar(20) | YES | MUL | NULL | | | StudentAge | int(11) | YES | | NULL | | | StudentCountryName | varchar(100) | YES | | NULL | | +--------------------+--------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec)