Extracting values from JSON column using KQL (Azure Data Explorer)

Can you please tell me how to extract values of category, enabled and categoryGroup from the below JSON column in KQL(Azure Data Explorer).

Below JSON value is exactly what I see in the column called "Logs". I see that the Column Logs is defined as string datatype in table

AzLogsCoverage 
| extend Logs = case(isnull(Logs) or isempty(Logs), 'N/A', Logs)
| where Logs <> 'N/A'
| project Logs
| extend LogsCategory = parse_json(Logs).category

[
  {
    "category": "Administrative",
    "enabled": true,
    "categoryGroup": null
  },
  {
    "category": "Security",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "ServiceHealth",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Alert",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Recommendation",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Policy",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Autoscale",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "ResourceHealth",
    "enabled": false,
    "categoryGroup": null
  }
]

>Solution :

if the input is of type string, you first need to invoke parse_json() on it, to make it of type dynamic.

Then, you can use mv-expand/mv-apply to expand elements in the array, and then you can explicitly project properties of interest for each element.

for example:

print input = ```[
  {
    "category": "Administrative",
    "enabled": true,
    "categoryGroup": null
  },
  {
    "category": "Security",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "ServiceHealth",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Alert",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Recommendation",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Policy",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "Autoscale",
    "enabled": false,
    "categoryGroup": null
  },
  {
    "category": "ResourceHealth",
    "enabled": false,
    "categoryGroup": null
  }
]```
| extend d = parse_json(input)
| mv-apply d on (
    project Category = tostring(d.category),
            Enabled = tobool(d.enabled),
            CategoryGroup = tostring(d.categoryGroup)
)
| project-away input