Book Image

Learning Google BigQuery

By : Thirukkumaran Haridass, Mikhail Berlyant, Eric Brown
Book Image

Learning Google BigQuery

By: Thirukkumaran Haridass, Mikhail Berlyant, Eric Brown

Overview of this book

Google BigQuery is a popular cloud data warehouse for large-scale data analytics. This book will serve as a comprehensive guide to mastering BigQuery, and how you can utilize it to quickly and efficiently get useful insights from your Big Data. You will begin with getting a quick overview of the Google Cloud Platform and the various services it supports. Then, you will be introduced to the Google BigQuery API and how it fits within in the framework of GCP. The book covers useful techniques to migrate your existing data from your enterprise to Google BigQuery, as well as readying and optimizing it for analysis. You will perform basic as well as advanced data querying using BigQuery, and connect the results to various third party tools for reporting and visualization purposes such as R and Tableau. If you're looking to implement real-time reporting of your streaming data running in your enterprise, this book will also help you. This book also provides tips, best practices and mistakes to avoid while working with Google BigQuery and services that interact with it. By the time you're done with it, you will have set a solid foundation in working with BigQuery to solve even the trickiest of data problems.
Table of Contents (9 chapters)
Free Chapter
Google Cloud and Google BigQuery

Converting data

When working with data, situations will arise where data will need to be converted from one type to another. For instance, an analyst might receive date in a format that BigQuery does not support. When loaded, BigQuery will automatically detect the type as a string. If the analyst wants to do any type of date arithmetic, they will need to convert the string to a date.

The following is a list of all types that can be cast into other types:

  • Casting can be achieved using the CAST() function:

For instance, if I want to cast a Boolean into an integer: CAST(X AS INT64).

The SAFE_CAST() function can be used to return a NULL value instead of an error when a cast is unsuccessful.
  • Strings of the format YYYY-DD-MM can be cast to Date, Datetime, or Timestamp: CAST(X AS DATE). In the case of casting to Datetime or Timestamp...