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Troubleshooting and Solving Data Join Pitfalls

Troubleshooting and Solving Data Join Pitfalls

1시간 크레딧 5개

GSP412

Google Cloud Self-Paced Labs

Overview

BigQuery is Google's fully managed, NoOps, low cost analytics database. With BigQuery you can query terabytes and terabytes of data without having any infrastructure to manage or needing a database administrator. BigQuery uses SQL and can take advantage of the pay-as-you-go model. BigQuery allows you to focus on analyzing data to find meaningful insights.

Joining data tables can provide meaningful insight into your dataset. However when you join your data, there are common pitfalls that could corrupt your results. This lab focuses on avoiding those pitfalls. Types of joins:

  • Cross join: combines each row of the first dataset with each row of the second dataset, where every combination is represented in the output.
  • Inner join: requires that key values exist in both tables for the records to appear in the results table. Records appear in the merge only if there are matches in both tables for the key values.
  • Left join: Each row in the left table appears in the results, regardless of whether there are matches in the right table.
  • Right join: the reverse of a left join. Each row in the right table appears in the results, regardless of whether there are matches in the left table.

For more information about joins, see Join Page.

The dataset you'll use is an ecommerce dataset that has millions of Google Analytics records for the Google Merchandise Store loaded into BigQuery. You have a copy of that dataset for this lab and will explore the available fields and row for insights.

For syntax information to help you follow and update the queries, see Standard SQL Query Syntax.

What you'll do

In this lab, you perform these tasks:

  • Use BigQuery to explore a dataset

  • Troubleshoot duplicate rows in a dataset

  • Create joins between data tables

  • Understand each join type

이 실습의 나머지 부분과 기타 사항에 대해 알아보려면 Qwiklabs에 가입하세요.

  • Google Cloud Console에 대한 임시 액세스 권한을 얻습니다.
  • 초급부터 고급 수준까지 200여 개의 실습이 준비되어 있습니다.
  • 자신의 학습 속도에 맞춰 학습할 수 있도록 적은 분량으로 나누어져 있습니다.
이 실습을 시작하려면 가입하세요
점수

—/100

Create a new dataset

단계 진행

/ 25

Identify a key field in your ecommerce dataset

단계 진행

/ 25

Pitfall: non-unique key

단계 진행

/ 25

Join pitfall solution

단계 진행

/ 25