Parsing JSON from SQL Server - sql

Question

I have a table with the following columns, one column being a JSON blob. I'm unclear how to parse the JSON blob as a series of columns alongside the other columns. I know there's something called OPENJSON, but not sure how to apply it to this case.
ID | ORGANIZATION | DEVICE_TIME | DEVICE | DATA
--------------------------------------------------------------------
011 015 2021-07-20 015 (JSON COLUMN)
012 016 2021-08-20 016 (JSON COLUMN)
The json string example is below, from the DATA column above
{
"device": {
"battery_level": 98,
"rssi": -105,
"boot_cnt": 5,
"apn": "teal",
"ip_addr": "10.176.30.171",
"fw_ver": "1.00",
"modem_fw": "mfw_nrf9160_1.3.0",
"imsi": "234500024531391",
"imei": "352656101040510",
"iccid": "8901990000000534985"
},
"data": {
"Temperature": 77.563942718505871,
"Humidity": 29.100597381591797,
"pressure": 28.883883226248145,
"air_quality": 37.067466735839844,
"SoilMoisture": 0.42462845010615713,
"Lat": 0,
"Long": 0,
"Alt": 0
}
}

Answer 1

openjson returns a table (possibly with many rows, although not for your sample).
To put something into a column you need a scalar. Try this example. Yes you need to explicitly list the columns out.
/* Create a sample table */
WITH MySampleTable
AS (
SELECT 1 as col1, 2 as col2, 'Hi There' as col3,
CAST('
{
"device": {
"battery_level": 98,
"rssi": -105,
"boot_cnt": 5,
"apn": "teal",
"ip_addr": "10.176.30.171",
"fw_ver": "1.00",
"modem_fw": "mfw_nrf9160_1.3.0",
"imsi": "234500024531391",
"imei": "352656101040510",
"iccid": "8901990000000534985"
},
"data": {
"Temperature": 77.563942718505871,
"Humidity": 29.100597381591797,
"pressure": 28.883883226248145,
"air_quality": 37.067466735839844,
"SoilMoisture": 0.42462845010615713,
"Lat": 0,
"Long": 0,
"Alt": 0
}
}
'
AS NVARCHAR(MAX)
) as myjsoncolumn
UNION ALL
SELECT 5,6,'Test','
{
"device": {
"battery_level": 2,
"rssi": -105,
"boot_cnt": 5,
"apn": "teal"
},
"data": {
"Humidity": 29.100597381591797,
"pressure": 28.883883226248145
}
}
'
)
SELECT *,
JSON_VALUE(myjsoncolumn,'$.device.battery_level') as battery_level,
JSON_VALUE(myjsoncolumn,'$.data.Temperature') as Temp
FROM MySampleTable

Answer 2

The statement usually depends on the structure of the parsed JSON data. In this case, a possible option is OPENJSON() with explicit schema (the WITH clause with columns definitions), using the appropriate data types and path expressions:
JSON and table:
DECLARE #json varchar(max) = '{
"device": {
"battery_level": 98,
"rssi": -105,
"boot_cnt": 5,
"apn": "teal",
"ip_addr": "10.176.30.171",
"fw_ver": "1.00",
"modem_fw": "mfw_nrf9160_1.3.0",
"imsi": "234500024531391",
"imei": "352656101040510",
"iccid": "8901990000000534985"
},
"data": {
"Temperature": 77.563942718505871,
"Humidity": 29.100597381591797,
"pressure": 28.883883226248145,
"air_quality": 37.067466735839844,
"SoilMoisture": 0.42462845010615713,
"Lat": 0,
"Long": 0,
"Alt": 0
}
}'
SELECT *
INTO Data
FROM (VALUES
('011', '015', '2021-07-20', '015', #json),
('012', '016', '2021-08-20', '016', #json)
) v (ID, ORGANIZATION, DEVICE_TIME, DEVICE, DATA)
Statement:
SELECT d.*, j.*
FROM Data d
OUTER APPLY OPENJSON(d.DATA) WITH (
batery_level int '$.device.battery_level',
rssi int '$.device.rssi',
boot_cnt int '$.device.boot_cnt',
apn varchar(10) '$.device.boot_apn',
ip_addr varchar(19) '$.device.ip_addr',
fw_ver varchar(5) '$.device.fw_ver',
modem_fw varchar(59) '$.device.modem_fw',
imsi varchar(15) '$.device.imsi',
imei varchar(15) '$.device.imei',
iccid varchar(50) '$.device.iccid',
Temperature numeric(20, 15) '$.data.Temperature',
Humidity numeric(22, 18) '$.data.Humidity',
pressure numeric(22, 18) '$.data.pressure',
air_quality numeric(22, 18) '$.data.air_quality',
SoilMoisture numeric(22, 18) '$.data.SoilMoisture',
Lat numeric(9, 6) '$.data.Lat',
Long numeric(9, 6) '$.data.Long',
Alt numeric(9, 6) '$.data.Alt'
) j