Window Functions for Statistical Analysis
This chapter provides tutorial notes on Window Functions. Topics include introduction of window functions; OVER clause to identify window functions; PARTITION BY clause to form multiple windows; ROWS and RANGE clauses to specify moving frames; WINDOW clause to name windows.
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What Is Window Function
List of Window Functions
Order of Rows in Windows and Output
"PARTITION BY ..." for Multiple Windows
"ROWS|RANGE ..." for Moving Frames in Windows
"WINDOW ..." to Define Named Windows
- A window function is a function that can perform calculations
over a window (or range) of rows dynamically defined and referenced
by the current row in output rows.
- Some window functions are extended from aggregate functions like
"COUNT() OVER ...", "SUM(...) OVER ...", "AVG(...) OVER ...",
MIN(...) OVER ...", "MAX(...) OVER ...", etc.
- Some other window functions take values from other output rows
relative to the current row or window boundary rows
like "ROW_NUMBER(...) OVER ...", "FIRST_VALUE(...) OVER ...",
"LAST_VALUE(...) OVER ... ", "NTH_VALUE(...) OVER ...",
- Some other window functions calculate statistical information
like "RANK() OVER ...", "DENSE_RANK() OVER ...", "CUME_DIST() OVER ...",
- "PARTITION BY ..." clause can be used in window functions to divided
output rows into multiple windows.
- "SORT BY ..." clause can be used in window function to re-arrange
the order of output rows within each window.
- "ROWS ..." clause can be used in window functions to create
moving frames using row counts as parameters.
- "RANGE ..." clause can be used in window functions to create
moving frames using value differences of a given expression.
- "WINDOWS ..." clause can be used at the SELECT statement level
to define named windows to be used by window functions.
Table of Contents
About This Book
Introduction of SQL
MySQL Introduction and Installation
Introduction of MySQL Programs
PHP Programs and MySQL Server
Perl Programs and MySQL Servers
Java Programs and MySQL Servers
Datatypes and Data Literals
Operations and Expressions
Character Strings and Bit Strings
Commonly Used Functions
Table Column Types for Different Types of Values
Using DDL to Create Tables and Indexes
Using DML to Insert, Update and Delete Records
Using SELECT to Query Database
►Window Functions for Statistical Analysis
Use Index for Better Performance
Transaction Management and Isolation Levels
Locks Used in MySQL
Defining and Calling Stored Procedures
Variables, Loops and Cursors Used in Stored Procedures
System, User-Defined and Stored Procedure Variables
MySQL Server Administration
Storage Engines in MySQL Server
InnoDB Storage Engine - Primary and Secondary Indexes
Performance Tuning and Optimization
Bulk Changes on Large Tables
MySQL Server on macOS
Installing MySQL Server on Linux
Connection, Performance and Second Instance on Linux
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