MySQL Create Index

Last Updated: 01 July, 2023

In MySQL, we can create an index on a table to improve the performance of queries that involve searching, sorting, and filtering data. Indexes help the database engine quickly find the required data without scanning the entire table.

To create an index in MySQL, we can use the CREATE INDEX statement.

The syntax for creating an index in MySQL is as follows:

 CREATE INDEX index_name
 ON table_name (column1, column2, ...);

Here's an example that demonstrates how to create an index named "idx_lastname" on the "employees" table for the "last_name" column:

 CREATE INDEX idx_lastname
 ON employees (last_name);

This statement creates a non-unique index on the "last_name" column of the "employees" table. We can use the same syntax to create indexes on multiple columns by listing them within the parentheses.

It's important to note that creating an index can have both positive and negative impacts on performance. While it can improve the speed of data retrieval for certain queries, it also incurs additional overhead during data modification operations like inserts, updates, and deletes. Therefore, it's essential to carefully analyze our query patterns and consider the trade-offs before creating an index.