sql statement: Add syntax gram of load stats (#2926)

TOC.md

@@ -187,6 +187,7 @@
       - [`INSERT`](/sql-statements/sql-statement-insert.md)
       - [`KILL [TIDB]`](/sql-statements/sql-statement-kill.md)
       - [`LOAD DATA`](/sql-statements/sql-statement-load-data.md)
+      - [`LOAD STATS`](/sql-statements/sql-statement-load-stats.md)
       - [`MODIFY COLUMN`](/sql-statements/sql-statement-modify-column.md)
       - [`PREPARE`](/sql-statements/sql-statement-prepare.md)
       - [`RENAME INDEX`](/sql-statements/sql-statement-rename-index.md)

sql-statements/sql-statement-load-stats.md

@@ -0,0 +1,37 @@
+---
+title: LOAD STATS
+summary: An overview of the usage of LOAD STATS for the TiDB database.
+category: reference
+---
+
+# LOAD STATS
+
+The `LOAD STATS` statement is used to load the statistics into TiDB.
+
+## Synopsis
+
+**LoadStatsStmt:**
+
+![LoadStatsStmt](/media/sqlgram/LoadStatsStmt.png)
+
+## Examples
+
+You can access the address `http://${tidb-server-ip}:${tidb-server-status-port}/stats/dump/${db_name}/${table_name}` to download the TiDB instance's statistics.
+
+You can also use `LOAD STATS ${stats_path}` to load the specific statistics file.
+
+The `${stats_path}` can be an absolute path or a relative path. If you use a relative path, the corresponding file is found starting from the path where `tidb-server` is started. Here is an example:
+
+{{< copyable "sql" >}}
+
+```sql
+LOAD STATS '/tmp/stats.json';
+```
+
+```
+Query OK, 0 rows affected (0.00 sec)
+```
+
+## See also
+
+* [Statistics](/statistics.md)