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Hierarchical and Recursive Queries in SQL Server

Learn how to write recursive queries and query hierarchical data structures.

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4 Hours13 Videos47 Exercises7,701 Learners
3800 XP

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Course Description

Do you want to query complex data structures in an iterative way? Do you have access to hierarchical data structures that need to be queried? This course will teach you the tools required to solve these questions. You will learn how to write recursive queries and query hierarchical data structures. To do this, you will use Common Table Expressions (CTE) and the recursion principle on a wide variety of datasets. You will, for example, dig into a flight plan dataset and learn how to find the best and cheapest connection between two airports. After completing this course, you will understand the principle of recursion, and be able to identify and create hierarchical data models.

  1. 1

    Recursion and Common Table Expression (CTE)

    Free

    In this chapter, you will learn about recursion and why it is beneficial to apply this technique. You will also refresh your knowledge about Common Expression Tables (CTE).

    Play Chapter Now
    Recap of Common Table Expressions (CTE)
    50 xp
    A CTE is ... Find the wrong fact!
    50 xp
    A CTE for IT-positions
    100 xp
    A CTE for high-paid IT-positions
    100 xp
    Introduction to recursion
    50 xp
    Facts about recursion.
    50 xp
    Calculate the factorial of 5
    100 xp
    How to query the factorial of 6 recursively
    100 xp
    Solve recursive maths problems
    50 xp
    Counting numbers recursively
    100 xp
    Calculate the sum of potencies
    100 xp
  2. 2

    Hierarchical and Recursive Queries

    In this chapter, you will learn about recursive CTEs, how to query hierarchical datasets, and finally, how to apply recursive CTEs on hierarchical data.

    Play Chapter Now
    Introduction to recursive CTE
    50 xp
    Right or wrong?
    50 xp
    Create the alphabet recursively
    100 xp
    Create a time series of a year
    100 xp
    Working with recursive queries
    50 xp
    Who is your manager?
    100 xp
    Get the hierarchy position
    100 xp
    Which supervisor do I have?
    100 xp
    Analyze the family tree
    50 xp
    Get the number of generations?
    100 xp
    Get all possible parents in one field?
    100 xp
  3. 3

    Creating Data Models on Your Own

    In this chapter, you will learn how to create and modify database tables. You will learn about relational and hierarchical data models, how they differ, and when each model should be used.

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    How to work with tables
    50 xp
    Creating a table
    100 xp
    Inserting and updating a table
    100 xp
    Deleting data and dropping table
    100 xp
    Changing a table structure
    100 xp
    Working with relational data models
    50 xp
    Defining primary and foreign keys
    100 xp
    Inserting data to person and order history
    100 xp
    Getting the number of orders & total costs
    100 xp
    Working with hierarchical data models
    50 xp
    Creating a hierarchical data model
    100 xp
    Networked and hierarchical models
    50 xp
    Creating a networked data model
    100 xp
  4. 4

    Hierarchical Queries of Real-World Examples

    In this chapter, you will practice your learnings about hierarchical and recursive querying on real-world problems, such as finding possible flight routes, assembling a car, and modeling a power grid.

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    Travel planning for flight data
    50 xp
    Get the anchor & recursive member
    50 xp
    Get all possible airports
    100 xp
    All flight routes from Vienna
    100 xp
    How to assemble a car?
    50 xp
    Create the parts list
    100 xp
    Create a car's bill of material
    100 xp
    Build up a BMW?
    100 xp
    Modeling a power grid
    50 xp
    Create a power grid
    100 xp
    Get power lines to maintain
    100 xp
    Summary of the course
    50 xp

Datasets

Power grid dataEmployee dataDepartment dataSalary dataBill of materials products dataBill of materials dataFlights data

Collaborators

Alex YaroshSara BillenMona Khalil

Prerequisites

Functions for Manipulating Data in SQL Server
Dominik Egarter Headshot

Dominik Egarter

Data Engineering Enthusiast

Dominik Egarter is IT architecture manager & data engineering enthusiast at Kelag, a power utility company in Austria. He is responsible for the data and information architecture and leads several data science and data engineering projects in the fields of predictive maintenance, telecommunication networks, power grid networks, and customer insights. Dominik regularly uses R and SQL to implement algorithms and apps (R Shiny apps) which could be used to enforce new business insights and makes data easy to use for everyone.
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