Book Image

Cracking the Data Science Interview

By : Leondra R. Gonzalez, Aaren Stubberfield
Book Image

Cracking the Data Science Interview

By: Leondra R. Gonzalez, Aaren Stubberfield

Overview of this book

The data science job market is saturated with professionals of all backgrounds, including academics, researchers, bootcampers, and Massive Open Online Course (MOOC) graduates. This poses a challenge for companies seeking the best person to fill their roles. At the heart of this selection process is the data science interview, a crucial juncture that determines the best fit for both the candidate and the company. Cracking the Data Science Interview provides expert guidance on approaching the interview process with full preparation and confidence. Starting with an introduction to the modern data science landscape, you’ll find tips on job hunting, resume writing, and creating a top-notch portfolio. You’ll then advance to topics such as Python, SQL databases, Git, and productivity with shell scripting and Bash. Building on this foundation, you'll delve into the fundamentals of statistics, laying the groundwork for pre-modeling concepts, machine learning, deep learning, and generative AI. The book concludes by offering insights into how best to prepare for the intensive data science interview. By the end of this interview guide, you’ll have gained the confidence, business acumen, and technical skills required to distinguish yourself within this competitive landscape and land your next data science job.
Table of Contents (21 chapters)
Free Chapter
1
Part 1: Breaking into the Data Science Field
4
Part 2: Manipulating and Managing Data
10
Part 3: Exploring Artificial Intelligence
16
Part 4: Getting the Job

Merging tables with joins

SQL joins are used to combine rows from two or more tables based on a related column between them, providing a complete view of the data. We previously hinted at these related columns as primary keys and foreign keys.

As a refresher, a primary key is a column (or a combination of columns) in a database table that uniquely identifies each row in that table. A foreign key, on the other hand, is a column or a combination of columns in a table that establishes a link or a relationship to the primary key of another table.

As we dive into SQL joins, we will put our knowledge of primary and foreign keys to work!

Note

When discussing SQL joins, we will mostly focus on joining two tables to simplify the concepts. Traditionally, two joined tables are referred to as the left table and the right table.

Inner joins

INNER JOIN selects records that have matching values in both tables. Figure 5.8 best demonstrates the logic of this join type:

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