Update 04-opentsdb-json.mdx

docs/en/07-develop/03-insert-data/04-opentsdb-json.mdx

@@ -48,7 +48,7 @@ Please refer to [OpenTSDB HTTP API](http://opentsdb.net/docs/build/html/api_http
 
 - In JSON protocol, strings will be converted to nchar type and numeric values will be converted to double type.
 - Only data in array format is accepted and so an array must be used even if there is only one row.
-
+- The defult child table name is generated by rules.You can configure smlChildTableName in taos.cfg to specify chile table names, for example, `smlChildTableName=tname`. You can insert `"tags": { "host": "web02","dc": "lga","tname":"cpu1"}` and the cpu1 table will be automatically created. Note that if multiple rows have the same tname but different tag_set values, the tag_set of the first row is used to create the table and the others are ignored.
 :::
 
 ## Examples
@@ -94,3 +94,6 @@ taos> select * from `meters.current`;
  2022-03-28 09:56:51.250 |              12.600000000 |               2.000000000 | California.SanFrancisco               |
 Query OK, 2 row(s) in set (0.004076s)
 ```
+## Query Examples
+If you want query the data of "tags": {"location": "California.LosAngeles", "groupid": 1}，here is the query sql：
+select * from `meters.voltage` where location="California.LosAngeles" and groupid=1