You're reading from Learn T-SQL Querying - Second Edition

Product typeBook

Published inFeb 2024

PublisherPackt

ISBN-139781837638994

Edition2nd Edition

Tools

SQL Server

Concepts

Database Administration

Authors (2):

Pedro Lopes

Pam Lahoud

View More author details

Introducing the Cardinality Estimator

Before we get started, it’s important to have a common frame of reference for a few terms that will be referenced throughout this book:

Cardinality: Cardinality in a database is defined as the number of records, also called tuples, in each table or view.
Density: This term represents the average number of duplicate values in each column or column set – in other words, the average distribution of unique values in the data. It’s defined as 1 divided by the number of distinct values.
Frequency: This term represents the average number of occurrences of a given value in a column or column set. It’s defined as the number of rows times the density.
Selectivity: This term represents the fraction of the row count that satisfies a given predicate, between zero and one. This is calculated as the predicate cardinality (Pc) divided by the table cardinality (Tc) multiplied by 100: (Pc ÷ Tc) × 100. As...

The rest of the page is locked

You have been reading a chapter from

Learn T-SQL Querying - Second Edition

Published in: Feb 2024Publisher: PacktISBN-13: 9781837638994

Authors (2)

Pedro Lopes

Pedro Lopes is a Program Manager in the Database Systems group, based in Redmond, WA, USA. He has over 19 years of industry experience and has been with Microsoft for 9 years. He is currently responsible for program management of Database Engine features for in-market and vNext versions of SQL Server, with a special focus on the Relational Engine. He has extensive experience with query performance troubleshooting and is a regular speaker at numerous conferences such as SQLBits, PASS Summit, SQLIntersection, Microsoft Ignite, and Microsoft Build. He blogs about SQL on the SQL Server Team blog. He has authored several tools in the Tiger toolbox on GitHub: AdaptiveIndexDefrag maintenance solution, BPCheck, and usp_WhatsUp.
Read more about Pedro Lopes

Pam Lahoud

Pam Lahoud is a Program Manager in the Database Systems group, based in Redmond, WA, USA. She has been with Microsoft for 13 years and is currently responsible for program management of Database Engine features for in-market and vNext versions of SQL Server, with a special focus on the Storage Engine area. She is passionate about SQL Server performance and has focused on performance tuning and optimization, particularly from the developer's perspective, throughout her career. She is a SQL Server 2008 Microsoft Certified Master (MCM) with over 20 years of experience working with SQL Server.
Read more about Pam Lahoud

Personalised recommendations for you

Based on your interests and search pattern

Et al.

Ever wonder why speech recognition systems don't understand the Scottish accent, or what would happen if an astronaut only ate mac 'n' cheese, or other spurious reflections you'd have at a bar? We did, then collated those deliberations into absurd research articles with fake figures and methodologies inspired by even more fictionally absurd studies.

BookAug 2023230 pages5

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

BookDec 2023360 pages4

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

BookDec 2023360 pages5

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

BookDec 2023360 pages1

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

BookDec 2023360 pages5

Mastering Tableau 2023

This book is a comprehensive resource to mastering your Tableau skills and becoming a BI expert. As you progress, you will learn how to build advanced dashboards and improve your storytelling to derive key business insight, as well as make you well-versed with advanced functionalities of Tableau in the business intelligence domain.

BookAug 2023684 pages

Building AI Applications with ChatGPT APIs

This guide covers all ChatGPT API features for effortless creation of robust AI powered apps. With its help, you’ll be able to leverage ChatGPT’s cutting-edge NLP models to take your app development skills to the next level. You’ll also work on ten exciting projects that will give you the practical know-how that you can apply to your existing applications.

BookSep 2023258 pages5

Building AI Applications with ChatGPT APIs

This guide covers all ChatGPT API features for effortless creation of robust AI powered apps. With its help, you’ll be able to leverage ChatGPT’s cutting-edge NLP models to take your app development skills to the next level. You’ll also work on ten exciting projects that will give you the practical know-how that you can apply to your existing applications.

BookSep 2023258 pages2

Data Engineering with AWS

Embark on a journey to master data engineering pipelines on AWS! Our book offers a hands-on experience of AWS services for ingesting, transforming, and consuming data. Whether you're an absolute beginner or someone with basic data engineering experience, this guide is an indispensable resource.

BookOct 2023636 pages5

Modern Data Architecture on AWS

Every organization wants an agile, performant, and cost-effective data platform that meets all their current and future business needs. Purpose-built AWS analytics services and their features play a big part in building such a modern data platform. This book brings to you all the design and architectural patterns that’ll help you achieve this goal.

BookAug 2023420 pages5

Practical Guide to Applied Conformal Prediction in Python

Discover the power of Conformal Prediction with the "Practical Guide to Applied Conformal Prediction in Python." Master the latest techniques to quantify uncertainty in machine learning and computer vision models, and seamlessly apply them to your industry applications.

BookDec 2023240 pages

TinyML Cookbook

With over 70 project-based recipes, the TinyML Cookbook is a practical guide that will help you to get the most out of your microcontrollers. It provides a comprehensive understanding of the theoretical foundations while giving you hands-on experience training ML models for deployment on Arduino Nano 33 BLE Sense, Raspberry Pi Pico, and SparkFun RedBoard Artemis Nano microcontrollers.

BookNov 2023664 pages

You're reading from Learn T-SQL Querying - Second Edition

Introducing the Cardinality Estimator

Unlock this book and the full library FREE for 7 days

Authors (2)

Et al.

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

Generative AI with LangChain

This book is a comprehensive introduction to LLMs and LangChain, demystifying the basic mechanics of LangChain, its functionalities, and the myriad of applications it can be integrated into.

Mastering Tableau 2023

Building AI Applications with ChatGPT APIs

Building AI Applications with ChatGPT APIs

Data Engineering with AWS

Embark on a journey to master data engineering pipelines on AWS! Our book offers a hands-on experience of AWS services for ingesting, transforming, and consuming data. Whether you're an absolute beginner or someone with basic data engineering experience, this guide is an indispensable resource.

Modern Data Architecture on AWS

Practical Guide to Applied Conformal Prediction in Python

Discover the power of Conformal Prediction with the "Practical Guide to Applied Conformal Prediction in Python." Master the latest techniques to quantify uncertainty in machine learning and computer vision models, and seamlessly apply them to your industry applications.

TinyML Cookbook