Metric aggregations (avg, sum, min, max) in Elasticsearch - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this average aggregation?

Given the following Elasticsearch aggregation query, what is the average value returned for the field price?

Elasticsearch

{
  "size": 0,
  "aggs": {
    "average_price": {
      "avg": {
        "field": "price"
      }
    }
  }
}

A {"aggregations":{"average_price":{"value":25.5}}}

B {"aggregations":{"average_price":{"value":50}}}

C {"aggregations":{"average_price":{"value":0}}}

D {"aggregations":{"average_price":{"value":null}}}

💡 Hint

The average aggregation calculates the mean of all values in the price field.

The average aggregation returns the mean of the price field values across all documents. Here, the expected average is 25.5.

❓ Predict Output

intermediate

What is the sum of the quantity field?

Consider this Elasticsearch aggregation query. What sum value will it return for the quantity field?

Elasticsearch

{
  "size": 0,
  "aggs": {
    "total_quantity": {
      "sum": {
        "field": "quantity"
      }
    }
  }
}

A {"aggregations":{"total_quantity":{"value":null}}}

B {"aggregations":{"total_quantity":{"value":100}}}

C {"aggregations":{"total_quantity":{"value":0}}}

D {"aggregations":{"total_quantity":{"value":50}}}

💡 Hint

Sum aggregation adds all values of the specified field.

The sum aggregation returns the total sum of all quantity values in the documents, which is 100 in this case.

❓ Predict Output

advanced

What is the minimum value returned by this aggregation?

Analyze this Elasticsearch aggregation query. What minimum value will it return for the rating field?

Elasticsearch

{
  "size": 0,
  "aggs": {
    "min_rating": {
      "min": {
        "field": "rating"
      }
    }
  }
}

A {"aggregations":{"min_rating":{"value":5}}}

B {"aggregations":{"min_rating":{"value":0}}}

C {"aggregations":{"min_rating":{"value":1}}}

D {"aggregations":{"min_rating":{"value":null}}}

💡 Hint

Minimum aggregation finds the smallest value in the field.

The minimum aggregation returns the smallest rating value found in the documents, which is 1 here.

❓ Predict Output

advanced

What maximum value does this aggregation return?

Given this Elasticsearch aggregation query, what is the maximum value returned for the score field?

Elasticsearch

{
  "size": 0,
  "aggs": {
    "max_score": {
      "max": {
        "field": "score"
      }
    }
  }
}

A {"aggregations":{"max_score":{"value":99}}}

B {"aggregations":{"max_score":{"value":0}}}

C {"aggregations":{"max_score":{"value":null}}}

D {"aggregations":{"max_score":{"value":50}}}

💡 Hint

Maximum aggregation finds the largest value in the field.

The maximum aggregation returns the highest score value found in the documents, which is 99 here.

🧠 Conceptual

expert

Which aggregation returns null value and why?

In Elasticsearch, when running a metric aggregation like avg, sum, min, or max on a field that has no matching documents, what value is returned and why?

A The aggregation returns the default value of the field type, like 0 for numbers.

B The aggregation returns 0 because Elasticsearch assumes zero when no data is found.

C The aggregation throws a runtime error indicating no data found.

D The aggregation returns <code>null</code> because there are no documents to calculate the metric.

💡 Hint

Think about what happens when there is no data to aggregate.

When no documents match the query, metric aggregations return null because there is no value to compute. They do not default to zero or throw errors.