NONCLUSTERED INDEX
NONCLUSTERED INDEX is a SQL statement in the Indexes category. A separate structure containing index keys with pointers to the actual data rows. Multiple per table. The syntax is CREATE NONCLUSTERED INDEX index_name ON table (column) [INCLUDE (cols)];. It returns nonclustered index. A typical example: CREATE NONCLUSTERED INDEX idx_name ON employees (last_name); -- Separate B-tree: last_name -> row pointer -- Nonclustered = good for precise lookups, slower for range scans vs clustered -- With INCLUDE (covering index): CREATE NONCLUSTERED INDEX idx_emp ON employees (dept_id) INCLUDE (name, salary); A close relative is CREATE INDEX, which creates an index on one or more columns to speed up query performance. 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. More about this category: Database indexes — CREATE INDEX, UNIQUE INDEX, COMPOSITE INDEX, DROP INDEX.