Query data in the Viam app

Explore and analyze your captured data using SQL or MQL queries. You can run queries interactively in the Viam app’s query editor or programmatically through the SDK for ad-hoc analysis, building dashboards, or integrating with your own tools.

Tabular data (sensor readings, motor positions, encoder ticks, and other structured key-value data) is queryable through SQL and MQL. Binary data (images, point clouds) is stored separately and accessible through the data client API.

Open the query editor

1. Go to app.viam.com.
2. Click the DATA tab in the top navigation.
3. Click Query to open the query editor.
4. Select SQL or MQL mode depending on which language you want to use.

SQL is good for straightforward filtering, sorting, and limiting. MQL (MongoDB Query Language) uses aggregation pipelines and is more powerful for grouping, computing averages, and restructuring nested data.

By default, queries run against the readings collection in the sensorData database. See Query reference for the full schema.

Explore your data with basic SQL

Start with a broad query to see what data you have:

SELECT time_received, component_name, component_type, data
FROM readings
ORDER BY time_received DESC
LIMIT 10

This shows the 10 most recent readings across all components. Most of the interesting values are in the data column, which contains your actual readings as nested JSON.

To see the structure of your data, run this query for a specific component:

SELECT data FROM readings WHERE component_name = 'my-sensor' LIMIT 1

Switch to table view (the table icon in the results area) to see nested fields automatically flattened into dot-notation column headers like data.readings.temperature. These dot-notation paths are exactly what you use in your queries to extract specific values.

For the full schema and per-component examples, see the readings table schema.

To narrow to a specific component:

SELECT time_received, data
FROM readings
WHERE component_name = 'my-sensor'
ORDER BY time_received DESC
LIMIT 10

To filter by time range:

SELECT time_received, component_name, data
FROM readings
WHERE time_received > '2025-01-15T00:00:00Z'
  AND time_received < '2025-01-16T00:00:00Z'
ORDER BY time_received ASC

Extract fields from nested JSON

The data column contains JSON, so you need JSON functions to extract specific values. Use dot notation to reach into the nested structure:

SELECT
  time_received,
  data.readings.temperature AS temperature,
  data.readings.humidity AS humidity
FROM readings
WHERE component_name = 'my-sensor'
ORDER BY time_received DESC
LIMIT 20

For detection results from a vision service:

SELECT
  time_received,
  data.detections
FROM readings
WHERE component_name = 'my-detector'
  AND component_type = 'rdk:service:vision'
ORDER BY time_received DESC
LIMIT 10

To filter by a specific machine:

SELECT time_received, component_name, data
FROM readings
WHERE robot_id = 'YOUR-MACHINE-ID'
ORDER BY time_received DESC
LIMIT 10

Write MQL aggregation pipelines

Switch to MQL mode in the query editor. MQL queries are JSON arrays where each element is a pipeline stage.

Get the last 10 readings from a component:

[
  { "$match": { "component_name": "my-sensor" } },
  { "$sort": { "time_received": -1 } },
  { "$limit": 10 },
  {
    "$project": {
      "time_received": 1,
      "data": 1,
      "_id": 0
    }
  }
]

Count readings per component:

[
  {
    "$group": {
      "_id": "$component_name",
      "count": { "$sum": 1 }
    }
  },
  { "$sort": { "count": -1 } }
]

Count readings per component over a specific time window:

[
  {
    "$match": {
      "time_received": {
        "$gte": { "$date": "2025-01-15T00:00:00Z" },
        "$lt": { "$date": "2025-01-16T00:00:00Z" }
      }
    }
  },
  {
    "$group": {
      "_id": "$component_name",
      "count": { "$sum": 1 }
    }
  },
  { "$sort": { "count": -1 } }
]

Compute average, min, and max of a sensor value:

[
  { "$match": { "component_name": "my-sensor" } },
  {
    "$group": {
      "_id": null,
      "avg_temperature": { "$avg": "$data.readings.temperature" },
      "min_temperature": { "$min": "$data.readings.temperature" },
      "max_temperature": { "$max": "$data.readings.temperature" },
      "total_readings": { "$sum": 1 }
    }
  }
]

Group readings by hour to see trends over time:

[
  { "$match": { "component_name": "my-sensor" } },
  {
    "$group": {
      "_id": {
        "$dateToString": {
          "format": "%Y-%m-%d %H:00",
          "date": "$time_received"
        }
      },
      "avg_temperature": { "$avg": "$data.readings.temperature" },
      "count": { "$sum": 1 }
    }
  },
  { "$sort": { "_id": 1 } }
]

Find all detections above a confidence threshold:

[
  { "$match": { "component_name": "my-detector" } },
  { "$unwind": "$data.detections" },
  { "$match": { "data.detections.confidence": { "$gte": 0.9 } } },
  {
    "$project": {
      "time_received": 1,
      "class_name": "$data.detections.class_name",
      "confidence": "$data.detections.confidence",
      "_id": 0
    }
  },
  { "$sort": { "time_received": -1 } },
  { "$limit": 20 }
]

The $unwind stage is important when your data contains arrays. It flattens the array so each element becomes its own document, which you can then filter and project individually.

Query from code

You can run the same SQL and MQL queries from Python or Go using the data client API. See Query data from code for setup instructions and examples.

Try it

To get oriented with your own data:

1. Open the query editor and run SELECT DISTINCT component_name FROM readings to see what components have captured data.
2. Pick a component and run SELECT data FROM readings WHERE component_name = 'YOUR-COMPONENT' LIMIT 1 to see the JSON structure of its readings.
3. Use the field names from step 2 to write a query that extracts a specific value with dot notation (for example, data.readings.temperature).

For the full schema of the readings table, see Query reference.

Troubleshooting

What’s next

• Create a data pipeline: create precomputed summaries for faster queries.
• Hot data store: query a rolling window of recent data with lower latency.
• Sync data to your database: export data to your own MongoDB instance.
• Visualize data: build dashboards from your captured data.