Indexes

Author: learning-zone

mysql-queries.md

@@ -89,3 +89,14 @@ A view is a virtual table that is a result of a query. They can be extremely use
 |Sl.No|Query            | Description                                       |
 |-----|-----------------|---------------------------------------------------|
 | 01. |CREATE VIEW view1 AS SELECT c1, c2 FROM t1 WHERE condition|Create a view, comprising of columns c1 and c2 from a table named t1 where a certain condition has been met.|
+
+
+#### Indexes
+
+An index is used to speed up the performance of queries by reducing the number of database pages that have to be visited:
+
+|Sl.No|Query                               | Description                                       |
+|-----|------------------------------------|---------------------------------------------------|
+| 01. |CREATE INDEX index_nameON t(c1, c2) |Create an index on columns c1 and c2 of the table t |
+| 02. |CREATE UNIQUE INDEX index_name ON t(c3, c4) |Create a unique index on columns c3 and c4 of the table t |
+| 03. |DROP INDEX index_name |Drop an index |