What Is Struct Data Type BigQuery?


Scott Campbell

The Struct data type in BigQuery is a powerful feature that allows you to organize and structure your data in a hierarchical manner. It is particularly useful when dealing with complex and nested data structures. In this article, we will explore what the Struct data type is, how it works, and some practical examples of how to use it in BigQuery.

What is the Struct Data Type?

In simple terms, a Struct is a collection of named fields, where each field has its own data type. It is similar to a struct or record in other programming languages. By using the Struct data type, you can group related information together and treat it as a single entity.

Each field within a Struct has a name and a corresponding data type. The supported data types for fields within a Struct include:

  • STRING: Represents textual data.
  • INTEGER: Represents whole numbers.
  • FLOAT: Represents decimal numbers.
  • BOOLEAN: Represents true/false values.
  • STRUCT: Allows nesting of structures within structures.
  • ARRAY: Represents an array or list of values of the same type.

The ability to nest structures within other structures and create arrays of structs makes the Struct data type incredibly flexible and powerful for handling complex datasets.

How Does the Struct Data Type Work?

To define a field as a Struct in BigQuery, you simply need to specify its name followed by its data type using the dot notation. For example:

fieldName STRUCT<
  subField1 INT64,
  subField2 STRING,
  subField3 STRUCT<
    nestedSubField1 FLOAT64,
    nestedSubField2 ARRAY<INT64>

In the above example, we have defined a field named fieldName as a Struct, which contains three subfields: subField1, subField2, and subField3. The subField3 itself is another Struct that contains two nested subfields: nestedSubField1 of type FLOAT64 and nestedSubField2, which is an array of INT64 values.

Accessing Fields Within a Struct

To access the fields within a Struct, you can use the dot notation. For example, to access the value of subField1 within the fieldName field, you would use:


You can also access nested fields within a Struct by chaining the dot notation. For example, to access the value of nestedSubField1 within the nestedSubField3, you would use:


Practical Examples of Using the Struct Data Type in BigQuery

Example 1: Storing Customer Information

If you have a dataset containing customer information such as name, age, email address, and address, you can store it as a Struct in BigQuery. Here’s an example:

customer STRUCT<
  name STRING,
  age INT64,
  email STRING,
  address STRUCT<
    street STRING,
    city STRING,
    state STRING,
    country STRING

By storing the customer information as a Struct, you can easily retrieve and manipulate the data as a single entity.

Example 2: Analyzing Sensor Data

Let’s say you have a dataset containing sensor data from various devices. Each device has a unique ID, and for each device, you have multiple readings for temperature, humidity, and pressure.

You can store this data as a Struct in BigQuery. Here’s an example:

device STRUCT<
  id INT64,
  readings ARRAY<STRUCT<
    temperature FLOAT64,
    humidity FLOAT64,
    pressure FLOAT64

By using the Struct data type to group the device ID with its corresponding sensor readings, you can perform powerful analytics and queries on the data.


The Struct data type in BigQuery is a valuable tool for organizing and structuring complex datasets. It allows you to group related information together and treat it as a single entity.

By leveraging the power of nested structures and arrays of structs, you can handle even the most intricate datasets with ease. Start using the Struct data type in your BigQuery projects to unlock its full potential!

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