CREATE INDEX

CREATE INDEX is a SQL statement in the Indexes category. Creates an index on one or more columns to speed up query performance. The syntax is CREATE [UNIQUE] INDEX index_name ON table_name (column1, column2, ...);. It returns index. A typical example: CREATE INDEX idx_last_name ON employees (last_name); -- Speeds up: SELECT * FROM employees WHERE last_name = 'Smith' CREATE UNIQUE INDEX idx_email ON users (email); -- Index + uniqueness constraint A close relative is DROP INDEX, which removes an existing index from a table. A close relative is COMPOSITE INDEX, which an index on multiple columns. Column order matters — queries use leftmost prefix. A close relative is EXPLAIN, which shows how MySQL executes a query — which indexes are used, table scan vs index scan. More about this category: Database indexes — CREATE INDEX, UNIQUE INDEX, COMPOSITE INDEX, DROP INDEX. Related Indexes entries: DROP INDEX, COMPOSITE INDEX, EXPLAIN, FULLTEXT INDEX, SPATIAL INDEX, INCLUDE INDEX (Covering Index), PARTIAL INDEX, INVISIBLE INDEX.