BTREE is a type of index used in MySQL to optimize the performance of queries. It is based on a balanced tree structure, where each node stores a range of values and pointers to its child nodes.
When data is indexed using BTREE, queries that involve filtering or sorting by the indexed columns can quickly locate the relevant rows without having to scan the entire table. This can significantly improve the speed of query execution and reduce the load on the database server.
BTREE indexes are commonly used for columns that have high selectivity, meaning they contain a large number of distinct values compared to the total number of rows in the table. Examples include primary keys, foreign keys, and frequently searched columns.
To use BTREE indexing in MySQL, you can specify it as the index type when creating or altering a table. For example:
CREATE TABLE mytable (
id INT PRIMARY KEY,
name VARCHAR(50),
age INT,
INDEX idx_age USING BTREE (age)
);
In this example, an index named idx_age is created on the age column using BTREE. This will optimize queries that involve filtering or sorting by age.
