The SQL CREATE INDEX statement is used to create an index on a table in a database. Indexes are used to improve the speed of data retrieval operations on a table, such as SELECT queries, by providing faster access to rows based on the indexed columns.
Here's the basic syntax of the CREATE INDEX statement:
CREATE INDEX index_name
ON table_name (column1, column2, ...);
index_name: The name of the index to be created. This should be unique within the database.table_name: The name of the table on which the index is being created.(column1, column2, ...): The column or columns on which the index is being created. You can specify one or more columns here.Example:
CREATE INDEX idx_lastname ON employees (last_name);
This statement creates an index named idx_lastname on the last_name column of the employees table. This index will help to speed up queries that involve filtering or sorting by the last_name column.
It's important to note that while indexes can improve query performance, they also consume additional storage space and can impact the performance of data modification operations (e.g., INSERT, UPDATE, DELETE), as the index needs to be updated along with the underlying data. So, it's essential to carefully consider the columns on which to create indexes based on the