# Try To Read the Execution Plan
__*Implementation Plan*__
```8
tidb> ~!@DESC@!~ SELECT name FROM planets LIMIT 8;
+----------------------------+---------+-----------+---------------------------------+--------------------------------+
| id                         | estRows | task      | access object                   | operator info                  |
+----------------------------+---------+-----------+---------------------------------+--------------------------------+
| ~!@Limit_7@!~                    | 8.00    | root      |                                 | offset:0, count:8              |
| └─IndexReader_12           | 8.00    | root      |                                 | index:Limit_11                 |
|   └─Limit_11               | 8.00    | cop[tikv] |                                 | offset:0, count:8              |
|     └─IndexFullScan_10     | 8.00    | cop[tikv] | table:planets, index:name(name) | keep order:false, stats:pseudo |
+----------------------------+---------+-----------+---------------------------------+--------------------------------+
4 rows in set (0.01 sec)

tidb> ~!@EXPLAIN@!~ SELECT name FROM planets ORDER BY distance_from_sun LIMIT 8;
+------------------------------+---------+-----------+---------------+-------------------------------------------------------+
| id                           | estRows | task      | access object | operator info                                         |
+------------------------------+---------+-----------+---------------+-------------------------------------------------------+
| Projection_7                 | 8.00    | root      |               | planets.name                                          |
| └─~!@TopN_8@!~                     | 8.00    | root      |               | planets.distance_from_sun, offset:0, count:8          |
|   └─TableReader_15           | 8.00    | root      |               | data:TopN_14                                          |
|     └─TopN_14                | 8.00    | cop[tikv] |               | planets.distance_from_sun, offset:0, count:8          |
|       └─TableFullScan_13     | 9.00    | cop[tikv] | table:planets | keep order:false, stats:pseudo                        |
+------------------------------+---------+-----------+---------------+-------------------------------------------------------+
5 rows in set (0.00 sec)
```

------------------------------------------------------------
SQL is a declarative language. It describes what the query results should look like, not how they are actually retrieved. TiDB considers all possible ways to execute queries, including what order to join tables and whether any potential indexes can be used. The process of considering a query execution plan is called SQL tuning.

For more information about execution plans, see: `https://docs.pingcap.com/tidb/stable/explain-overview`