I am trying to access the data stored in a snowflake table using python sql. Below is the columns given below i want to access - sql

Question

Below is the data-sample and i want to access columns value,start. This data i dumped in one column(DN) of a table (stg)
{
"ok": true,
"metrics": [
{
"name": "t_in",
"data": [{"value": 0, "group": {"start": "00:00"}}]
},
{
"name": "t_out",
"data": [{"value": 0,"group": {"start": "00:00"}}]
}
]
}
##consider many lines stored in same column in different rows.
Below query only fetched data for name. I want to access other columns value also. This query is a part of python script.
select
replace(DN : metrics[0].name , '"' , '')as metrics_name, #able to get
replace(DN : metrics[2].data , '"' , '')as metrics_data_value,##suggestion needed
replace(DN : metrics.data.start, '"','') as metrics_start, ##suggestion needed
replace(DN : metrics.data.group.finish, '"','') as metrics_finish, ##suggestion needed
from stg
Do i need to iterate over data and group? If yes, please suggest the code.

Answer 1

Here is an example of how to query that data.
Set up sample data:
create or replace transient table test_db.public.stg (DN variant);
insert overwrite into test_db.public.stg (DN)
select parse_json('{
"ok": true,
"metrics": [
{
"name": "t_in",
"data": [
{"value": 0, "group": {"start": "00:00"}}
]
},
{
"name": "t_out",
"data": [
{"value": 0,"group": {"start": "00:00"}}
]
}
]
}');
Select statement example:
select
DN:metrics[0].name::STRING,
DN:metrics[1].data,
DN:metrics[1].data[0].group.start::TIME,
DN:metrics[1].data[0].group.finish::TIME
from test_db.public.stg;
Instead of querying individual indexes of the JSON arrays, I think you'll want to use the flatten function which is documented here.
Here is how you do it with the flatten which is what I am guessing you want:
select
mtr.value:name::string,
dta.value,
dta.value:group.start::string,
dta.value:group.finish::string
from test_db.public.stg stg,
lateral flatten(input => stg.DN:metrics) mtr,
lateral flatten(input => mtr.value:data) dta