Introduction to MongoDB $log10 Operator

MongoDB is a popular NoSQL database that supports many operators and aggregation pipelines, including the $log10 operator. The $log10 operator is an aggregation pipeline operator used to calculate the base-10 logarithm of a given numeric value.

Syntax

The syntax of the $log10 operator is as follows:

{ $log10: <number> }

Where <number> is the number for which to calculate the base-10 logarithm. The input must be a numeric type, otherwise an error will be returned.

Use Cases

The $log10 operator is commonly used in aggregation pipeline operations to perform mathematical calculations on numeric data to generate new numeric results. For example, to calculate the logarithmic sales or logarithmic website traffic, the $log10 operator can be used.

Examples

Here are two examples of using the $log10 operator:

Example 1: Calculating the logarithmic sales

Assuming we have a collection that stores information about product sales, where each document contains the following fields:

{
  "product": "A",
  "sales": 1000
}

To calculate the logarithmic sales, we can use the following aggregation pipeline:

db.sales.aggregate([
  {
    $project: {
      product: 1,
      log10sales: { $log10: "$sales" }
    }
  }
])

The above pipeline selects the product and sales fields from the sales collection and uses the $log10 operator to calculate the logarithmic value of sales, storing the result in the new field log10sales. The result of running the above pipeline is:

{ "product": "A", "log10sales": 3 }

Example 2: Calculating the logarithmic website traffic

Assuming we have a collection that stores website traffic information, where each document contains the following fields:

{
  "page": "/about",
  "visitors": 5000
}

To calculate the logarithmic website traffic, we can use the following aggregation pipeline:

db.visits.aggregate([
  {
    $project: {
      page: 1,
      log10visitors: { $log10: "$visitors" }
    }
  }
])

The above pipeline selects the page and visitors fields from the visits collection and uses the $log10 operator to calculate the logarithmic value of visitors, storing the result in the new field log10visitors. The result of running the above pipeline is:

{ "page": "/about", "log10visitors": 3.7 }

Conclusion

The $log10 operator is an aggregation pipeline operator used to calculate the base-10 logarithm of a given number.