---
title: Utility Statements
category: user guide
---

# Utility Statements

## `DESCRIBE` statement

The `DESCRIBE` and `EXPLAIN` statements are synonyms, which can also be abbreviated as `DESC`. See the usage of the `EXPLAIN` statement.

## `EXPLAIN` statement

```sql
{EXPLAIN | DESCRIBE | DESC}
    tbl_name [col_name]

{EXPLAIN | DESCRIBE | DESC}
    [explain_type]
    explainable_stmt

explain_type:
    FORMAT = format_name

format_name:
    "DOT"

explainable_stmt: {
    SELECT statement
  | DELETE statement
  | INSERT statement
  | REPLACE statement
  | UPDATE statement
}
```

For more information about the `EXPLAIN` statement, see [Understand the Query Execution Plan](understanding-the-query-execution-plan.md).

In addition to the MySQL standard result format, TiDB also supports DotGraph and you need to specify `FORMAT = "dot"` as in the following example:

```sql
create table t(a bigint, b bigint);
desc format = "dot" select A.a, B.b from t A join t B on A.a > B.b where A.a < 10;

TiDB > desc format = "dot" select A.a, B.b from t A join t B on A.a > B.b where A.a < 10;desc format = "dot" select A.a, B.b from t A join t B on A.a > B.b where A.a < 10;
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| dot contents                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|
digraph HashRightJoin_7 {
subgraph cluster7{
node [style=filled, color=lightgrey]
color=black
label = "root"
"HashRightJoin_7" -> "TableReader_10"
"HashRightJoin_7" -> "TableReader_12"
}
subgraph cluster9{
node [style=filled, color=lightgrey]
color=black
label = "cop"
"Selection_9" -> "TableScan_8"
}
subgraph cluster11{
node [style=filled, color=lightgrey]
color=black
label = "cop"
"TableScan_11"
}
"TableReader_10" -> "Selection_9"
"TableReader_12" -> "TableScan_11"
}
 |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

If the `dot` program (in the `graphviz` package) is installed on your computer, you can generate a PNG file using the following method:

```bash
dot xx.dot -T png -O

The xx.dot is the result returned by the above statement.
```

If the `dot` program is not installed on your computer, copy the result to [this website](http://www.webgraphviz.com/) to get a tree diagram:

![Explain Dot](../media/explain_dot.png)

## `USE` statement

```sql
USE db_name
```

The `USE` statement is used to switch the default database. If the table in SQL statements does not display the specified database, then use the default database.