MySQL CREATE INDEX
CREATE INDEX
In MySQL, an index can be created on a table when the table is created with CREATE TABLE command. Otherwise, CREATE INDEX enables to add indexes to existing tables. A multiple-column index can be created using multiple columns.
The indexes are formed by concatenating the values of the given columns.
CREATE INDEX cannot be used to create a PRIMARY KEY.
Syntax:
CREATE INDEX [index name] ON [table name]([column name]);
Arguments
Name | Description |
---|---|
index name | Name of the index. |
table name | Name of the table. |
column name | Name of the column. |
Example
Code:
CREATE INDEX autid ON newauthor(aut_id);
Explanation
The above MySQL statement will create an INDEX on 'aut_id' column for 'newauthor' table.
MySQL create UNIQUE INDEX
Create UNIQUE INDEX
Using CREATE UNIQUE INDEX, you can create an unique index in MySQL.
Example
Code:
CREATE UNIQUE INDEX newautid ON newauthor(aut_id);
Explanation
The above MySQL statement will create an UNIQUE INDEX on 'aut_id' column for 'newauthor' table.
MySQL create UNIQUE INDEX with index type
Create UNIQUE INDEX with index type
In MySQL, you can specify the type of the INDEX with CREATE INDEX command to set a type for the index.
Example
Code:
CREATE UNIQUE INDEX newautid ON newauthor(aut_id) USING BTREE;
Explanation
The above MySQL statement will create an INDEX on 'aut_id' column for 'newauthor' table by an INDEX TYPE BTREE.
Previous:
MySQL Constraintsr
Next:
MySQL ALTER TABLE
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