


MySQL: Resolving "The SELECT Would Examine More Than MAX_JOIN_SIZE Rows" Error
In MySQL, the error message "The SELECT would examine more than MAX_JOIN_SIZE rows" indicates that a SELECT query is estimating to examine a number of rows in a join greater than the maximum size allowed by the MAX_JOIN_SIZE system variable. This error typically occurs when working with large datasets or complex join operations.
To resolve this issue, you can optimize your SQL query by using the following techniques:
- Set SQL_BIG_SELECTS=1: For PHP users, set the SQL_BIG_SELECTS=1 flag before executing the main query. This will allow MySQL to handle larger join sizes.
- Increase MAX_JOIN_SIZE: If the query is still exceeding the maximum size, increase the value of the MAX_JOIN_SIZE variable. You can do this dynamically in your SQL statement using the syntax SET SQL_MAX_JOIN_SIZE=#.
- Optimize WHERE clause: Ensure that your WHERE clause is filtering out unwanted rows effectively and that the join conditions are specific.
- Use indexed joins: Create indexes on the columns used in join conditions to improve query performance.
Example with PHP:
<code class="php">$mysqli = new mysqli("localhost", "root", "password", "db"); $mysqli->query("SET SQL_BIG_SELECTS=1"); // Set it before the main query $results = $mysqli->query("SELECT a, b, c FROM test"); while ($row = $results->fetch_assoc()) { echo '<pre class="brush:php;toolbar:false">'; print_r($row); echo ''; }
Remember to adjust the host, username, password, and database name to match your specific environment.
The above is the detailed content of How to Resolve \'The SELECT Would Examine More Than MAX_JOIN_SIZE Rows\' Error in MySQL?. 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

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

SublimeText3 Mac version
God-level code editing software (SublimeText3)

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

Notepad++7.3.1
Easy-to-use and free code editor

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.
