conn.execute("create table s1_1 using s1 tags ('{\"k1\": \"v1\"}')")
```
Query JSON tag and table name from a stable.
```python
tags=conn.query("select info, tbname from s1").fetch_all_into_dict()
tags
```
The `tags` value is:
```python
[{'info':'{"k1":"v1"}','tbname':'s1_1'}]
```
To get value from JSON tag by key:
```python
k1=conn.query("select info->'k1' as k1 from s1").fetch_all_into_dict()
"""
>>> k1
[{'k1': '"v1"'}]
"""
```
Refer to [JSON type instructions](https://www.taosdata.com/en/documentation/taos-sql) for more usage of JSON type.
#### Using nanosecond in Python connector
So far Python still does not completely support nanosecond type. Please refer to the link 1 and 2. The implementation of the python connector is to return an integer number for nanosecond value rather than datatime type as what ms and us do. The developer needs to handle it themselves. We recommend using pandas to_datetime() function. If Python officially support nanosecond in the future, TAOS Data might be possible to change the interface accordingly, which mean the application need change too.
Json tag test case, include create table with json tag,
select json tag and query with json tag in where condition,
besides, include json tag in group by/order by/join/subquery.
Json tag test case, include create table with json tag, select json tag and query with json tag in where condition, besides, include json tag in group by/order by/join/subquery.
case1: [TD-12452] fix error if json tag is NULL
case2: [TD-12389] describe child table, tag length error if the tag is json tag
'''
return
...
...
@@ -515,6 +515,23 @@ class TDTestCase:
tdSql.query("select jtag->'tag3' from jsons1_16")
tdSql.checkData(0,0,'-2.111000000')
# test TD-12452
tdSql.execute("ALTER TABLE jsons1_1 SET TAG jtag=NULL")
tdSql.query("select jtag from jsons1_1")
tdSql.checkData(0,0,None)
tdSql.execute("CREATE TABLE if not exists jsons1_20 using jsons1 tags(NULL)")
tdSql.query("select jtag from jsons1_20")
tdSql.checkData(0,0,None)
tdSql.execute("insert into jsons1_21 using jsons1 tags(NULL) values(1591061628000, 11, false, '你就会','')")
