Tag：Query optimization
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Understand MySQL query optimization process
MySQL query optimization needs three steps: parsing, preprocessing and optimization. In these processes, errors may occur. This article will not discuss error handling in depth, but will help you understand how MySQL executes queries so that you can write better query statements. Parser and preprocessor At the beginning, the MySQL parser split the query into […]
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MySQL uses custom variables for query optimization
Optimize sort query An important feature of user-defined variable is that you can assign the result of mathematical calculation of the variable to the variable at the same time, similar to our i = I + 1 method. Here is an example to calculate the row number of a data table SET @rownum := 0; […]
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Summary of SQL query optimization knowledge points of MySQL 10 million level big data
1. In order to optimize the query, we should try to avoid full table scanning. First, we should consider building indexes on the columns involved in where and order by. 2. Try to avoid null value judgment on the field in the where clause, otherwise the engine will give up using the index and scan […]
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MySQL InnoDB index principle
Clustered index The InnoDB storage engine table is an index organization table, and the data in the table is stored in the order of primary keys. Its aggregate index is to construct a B + tree according to the order of the primary key of each table. The leaf nodes store the row records of […]
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Necessary SQL Query Optimization Skills to Improve Website Access Speed
In this article, I’ll show you how to identify queries that cause performance problems, how to identify their problems, and how to quickly fix them and other ways to speed up queries. You must know that a fast-accessing website can make users like it, help the site to improve its ranking from Google, and help […]