mysql create index on table

mysql create index on table

 

CREATE INDEX Syntax

Creates an index on a table. Duplicate values are allowed:

CREATE INDEX index_name
ON table_name (column1column2, …);

CREATE UNIQUE INDEX Syntax

Creates a unique index on a table. Duplicate values are not allowed:

CREATE UNIQUE INDEX index_name
ON table_name (column1column2, …);

Note: The syntax for creating indexes varies among different databases. Therefore: Check the syntax for creating indexes in your database.

CREATE INDEX Example

The SQL statement below creates an index named “idx_lastname” on the “LastName” column in the “Persons” table:

CREATE INDEX idx_lastname
ON Persons (LastName);

If you want to create an index on a combination of columns, you can list the column names within the parentheses, separated by commas:

CREATE INDEX idx_pname
ON Persons (LastName, FirstName);