Use of Lateral Flatten for JSON in Snowflake - json

Question

I have the following JSON as a variant field in snowflake. I get NULLS when querying the data as shown below - -
create or replace table car_sales
(
src variant
)
as
select parse_json(column1) as src
from values
('{
"MyData": {
"DataID": "16784",
"EmpFirstName": "Jenny",
"EmpLastName": "Test1",
"Description": "My Company Data",
"Assignment": [
{
"AssignentId": "1077",
"AssignentName": "Multi Location",
"AssignentDescription": "usa",
},
],
"salary": 21557
},
"Update": true
}') v;
When I query the data I get Nulls -
select value:AssignentId::string as "1ProductName"
from car_sales,
lateral flatten(input => src:Assignment);
Output is NULL
Can you help to troubleshoot why this is happening?

Answer 1

Try adding the MyData qualifier in the lateral flatten:
with car_sales(src) as (
select
parse_json(column1) as src
from
values
(
'{ "MyData": {
"DataID": "16784",
"EmpFirstName": "Jenny",
"EmpLastName": "Test1",
"Description": "My Company Data",
"Assignment": [
{
"AssignentId": "1077",
"AssignentName": "Multi Location",
"AssignentDescription": "usa",
},
],
"salary": 21557
}, "Update": true }'
)
)
select
value:AssignentId::string as "1ProductName"
from
car_sales,
lateral flatten(input => src:MyData:Assignment);
1ProductName
1077

Answer 2

You are trying to access the child node directly. Specify the parent node as well
select value:AssignentId::string as "1ProductName"
from car_sales,
lateral flatten(input => src:MyData:Assignment);
input => src:Assignment
should be
input => src:MyData:Assignment
Here is the query to read values for each key
select src:MyData.DataID::string as "DataID"
, src:MyData.EmpFirstName::string as "EmpFirstName"
, src:MyData.EmpLastName::string as "EmpLastName"
, src:MyData.Description::string as "Description"
, value:AssignentId::string as "AssignentId/1ProductName"
, value:AssignentName::string as "AssignentName"
, value:AssignentDescription::string as "AssignentDescription"
, src:MyData.salary::number as "salary"
, src:Update::boolean as "Update"
from car_sales,
lateral flatten(input => src:MyData:Assignment);