Table of Contents
Date Series from a Numbers Table
Redshift: Date Series using Window Functions
MySQL: Date Series using Variables
Home Database Mysql Tutorial Generate Series in Redshift and MySQL_MySQL

Generate Series in Redshift and MySQL_MySQL

Jun 01, 2016 pm 01:13 PM

A lot of the charts and tables made inPeriscopeare time series, and the queries behind them are often easier when you can join and aggregate against a list of dates. Not having a complete list of dates causes gaps in the results, changing them in a misleading way:

Generate Series in Redshift and MySQL_MySQL

Postgres has a great function for generating a list of dates (seeUse generate_series to get continuous results), and making a list of the last 60 days withgenerate_seriesis easy:

<code>select now()::date - generate_series(0, 59)</code>
Copy after login

Accomplishing the same thing in Redshift and MySQL requires a little more work.

Date Series from a Numbers Table

The simplest alternative togenerate_seriesis to create a table containing a continuous list of numbers, starting at 0, and select from that table. (If you have a table with a sequentialidcolumn and never delete rows from it, you can just select theidcolumn from that table instead of creating a new numbers table).

<code>select n from numbers;</code>
Copy after login

Returns this list of rows: 0, 1, 2, 3...

Now that you have a numbers table, convert each number into a date:

Redshift:

<code>select (getdate()::date - n)::date from numbers</code>
Copy after login

MySQL:

<code>select date_sub(date(now()), interval n day) from numbers</code>
Copy after login

A numbers table is more convenient than a dates table since it never needs to be refreshed with new dates.

Redshift: Date Series using Window Functions

If you don't have the option to create a numbers table, you can build one on the fly using a window function. All you need is a table that has at least as many rows as the number of dates desired. Using a window function, number the rows in any table to get a list of numbers, and then convert that to a list of dates:

<code>select row_number() over (order by true) as nfrom users limit 60</code>
Copy after login

And now creating the list of dates directly:

<code>select (getdate()::date - row_number() over (order by true))::date as nfrom users limit 60</code>
Copy after login

MySQL: Date Series using Variables

With variables in MySQL, we can generate a numbers table by treating a select statement as a for loop:

<code>set @n:=-1;select (select @n:= @n+1) nfrom users limit 60</code>
Copy after login

And now creating the list of dates directly:

<code>set @n:=date(now() + interval 1 day);select (select @n:= @n - interval 1 day) nfrom users limit 60</code>
Copy after login

Now that we've made a list of dates, aggregating and joining data from other tables for time series charts is a breeze!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Reduce the use of MySQL memory in Docker Reduce the use of MySQL memory in Docker Mar 04, 2025 pm 03:52 PM

This article explores optimizing MySQL memory usage in Docker. It discusses monitoring techniques (Docker stats, Performance Schema, external tools) and configuration strategies. These include Docker memory limits, swapping, and cgroups, alongside

How to solve the problem of mysql cannot open shared library How to solve the problem of mysql cannot open shared library Mar 04, 2025 pm 04:01 PM

This article addresses MySQL's "unable to open shared library" error. The issue stems from MySQL's inability to locate necessary shared libraries (.so/.dll files). Solutions involve verifying library installation via the system's package m

How do you alter a table in MySQL using the ALTER TABLE statement? How do you alter a table in MySQL using the ALTER TABLE statement? Mar 19, 2025 pm 03:51 PM

The article discusses using MySQL's ALTER TABLE statement to modify tables, including adding/dropping columns, renaming tables/columns, and changing column data types.

Run MySQl in Linux (with/without podman container with phpmyadmin) Run MySQl in Linux (with/without podman container with phpmyadmin) Mar 04, 2025 pm 03:54 PM

This article compares installing MySQL on Linux directly versus using Podman containers, with/without phpMyAdmin. It details installation steps for each method, emphasizing Podman's advantages in isolation, portability, and reproducibility, but also

What is SQLite? Comprehensive overview What is SQLite? Comprehensive overview Mar 04, 2025 pm 03:55 PM

This article provides a comprehensive overview of SQLite, a self-contained, serverless relational database. It details SQLite's advantages (simplicity, portability, ease of use) and disadvantages (concurrency limitations, scalability challenges). C

Running multiple MySQL versions on MacOS: A step-by-step guide Running multiple MySQL versions on MacOS: A step-by-step guide Mar 04, 2025 pm 03:49 PM

This guide demonstrates installing and managing multiple MySQL versions on macOS using Homebrew. It emphasizes using Homebrew to isolate installations, preventing conflicts. The article details installation, starting/stopping services, and best pra

How do I configure SSL/TLS encryption for MySQL connections? How do I configure SSL/TLS encryption for MySQL connections? Mar 18, 2025 pm 12:01 PM

Article discusses configuring SSL/TLS encryption for MySQL, including certificate generation and verification. Main issue is using self-signed certificates' security implications.[Character count: 159]

What are some popular MySQL GUI tools (e.g., MySQL Workbench, phpMyAdmin)? What are some popular MySQL GUI tools (e.g., MySQL Workbench, phpMyAdmin)? Mar 21, 2025 pm 06:28 PM

Article discusses popular MySQL GUI tools like MySQL Workbench and phpMyAdmin, comparing their features and suitability for beginners and advanced users.[159 characters]

See all articles