Fill missing dates in date range in MySQL
In some cases, you may encounter tables with missing dates within a date range. This may disrupt the data analysis and plotting process. To bridge this gap, MySQL provides a solution to fill in missing dates with specified numeric values.
Let us consider the example of a table that records scores associated with a specific date. If some dates are omitted, our goal is to complete them with placeholder values (e.g. 0) to get a contiguous range.
Meeting challenges
MySQL lacks native recursive functionality, but we can use the NUMBERS table trick to generate date sequences based on auto-incrementing columns.
Generate date sequence
- Create NUMBERS table:
DROP TABLE IF EXISTS `numbers`; CREATE TABLE `numbers` ( `id` int(10) unsigned NOT NULL auto_increment, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
- Fill table:
INSERT INTO `numbers` ( `id` ) VALUES ( NULL ); -- 添加足够多的空行以覆盖所需的日期范围
This will generate as many rows as the date range requires. (Note: The number of inserted rows needs to be adjusted according to the date range. Simply inserting NULL
cannot automatically generate enough rows)
- Construct date sequence:
SELECT DATE_ADD('2010-06-06', INTERVAL `n`.`id` - 1 DAY) FROM `numbers` `n` WHERE DATE_ADD('2010-06-06', INTERVAL `n`.`id` -1 DAY) <= '2010-06-14';
Replace the dates "2010-06-06" and "2010-06-14" with your desired start and end dates in YYYY-MM-DD format.
Fill in missing dates
- Create LEFT JOIN:
SELECT `x`.`timestamp` AS `timestamp`, COALESCE(`y`.`score`, 0) AS `cnt` FROM (SELECT DATE_FORMAT(DATE_ADD('2010-06-06', INTERVAL `n`.`id` - 1 DAY), '%Y-%m-%d') AS `timestamp` FROM `numbers` `n` WHERE DATE_ADD('2010-06-06', INTERVAL `n`.`id` - 1 DAY) <= '2010-06-14') x LEFT JOIN `y` ON STR_TO_DATE(`y`.`date`, '%Y-%m-%d') = `x`.`timestamp`;
Replace y
with your actual data table and adjust the date format accordingly. (It is recommended to use a unified YYYY-MM-DD
format to avoid problems caused by format conversion)
By executing this query, you get the complete set of dates in the specified range, where missing values are filled with the specified 0 value. (Note: numbers
The table needs to be pre-populated with enough rows to ensure that the entire date range is covered.)
The above is the detailed content of How to Fill Missing Dates in a MySQL Date Range?. For more information, please follow other related articles on the PHP Chinese website!

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

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

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

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

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

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

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]

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


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

WebStorm Mac version
Useful JavaScript development tools

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

Dreamweaver CS6
Visual web development tools

Atom editor mac version download
The most popular open source editor

SublimeText3 English version
Recommended: Win version, supports code prompts!
