From table building to the latest detailed explanation of the execution order of sql and MySQL query statements
Definition order of SELECT statement keywords Sequence number is keyword execution order: select distinct --------- 7777 ... from --------- 1111 ... join --------- 2222 ... on --------- 3333 ... where --------- 4444 ... group by --------- 5555 ... having --------- 6666 ... order by --------- 8UTF-8...
Posted by keigowei on Sun, 31 Oct 2021 17:25:02 +0530
Isolation level and concurrency of MySQL transactions
MySQL version: 8.0.271, Problems faced by concurrent transaction execution1. Dirty ReadIf transaction A reads the modified data of uncommitted transaction B, it means that dirty reading has occurred.2. Non repeatable readIf transaction B modifies the data read by uncommitted transaction A, it mUTF-8...
Posted by Tyche on Mon, 01 Nov 2021 06:08:21 +0530
[phase II] 1. Introduction to database
Introduction to mysql Database is an essential part of all enterprise projects. At present, the most popular open source database is mysql. Database introduction: The carrier of data storage in the operating system is file. Windows, Linux and MacOS are file based operating systems. Database sysUTF-8...
Posted by mikep on Mon, 01 Nov 2021 16:24:12 +0530
Mysql's sql statement is complete and basic, for personal notes only
SQL Classification Data Query Language (DQL): DQL is mainly used for querying data. Its basic structure is to query one or more data using a combination of select clause, from clause and where clause. Data Manipulation Language (DML): DML is mainly used for operations to add, modify and deleteUTF-8...
Posted by hoolahoops on Mon, 01 Nov 2021 23:06:44 +0530
MySQL log file
1. Error log 1.1 default path The default is on datadir/hostname.err 1.2 define your own location vim /etc/my.cnf log_error=/tmp/mysql3306.log restart systemctl restart mysqld see select @@log_error; 2. Binary log effect: 1. Master slave dependency binary 2. Log files are required for data recUTF-8...
Posted by N1CK3RS0N on Tue, 02 Nov 2021 09:09:32 +0530
[Java learning summary] MySQL and JDBC
1, MySQL overview 1. What is MySQL Concept: it is a popular open source, free relational database History: developed by Swedish MySQL AB company, it is currently a product of Oracle characteristic: Free, open source databaseCompact and fully functionalEasy to useIt can run on Windows or Linux oUTF-8...
Posted by revaaron on Tue, 02 Nov 2021 18:29:44 +0530
Mysql tuning summarizes N cases of Mysql index failure
This article has been received and entered Mysql tuning topic Summarize N cases of mysql index failure In mysql, the index is implemented by the storage engine. Different storage engines work differently. Since the default storage engine of MySQL is InnoDB, the following are examples based on IUTF-8...
Posted by Sinister747 on Wed, 03 Nov 2021 00:46:07 +0530
Mysql master synchronization (master-slave synchronization)
1, Environment description Host A: 192.168.3.106 Host B: 192.168.3.169 2, Install MySQL MySQL installation (Linux: centos)_ Yang BAABAA - CSDN blog new data warehouse Directory: / data/mysql / new log directory: / data/log/mysql1. Download the MySQL official website download tutorial_ Yang BAABUTF-8...
Posted by Fuzzy Wobble on Wed, 03 Nov 2021 13:57:56 +0530
MySQL Database (1/5) Installation Start Basic Operation
MySQL Database Analogue: Database--Folder, Datasheet--File, Row in File--Datasheet Record. Database management system: DBMS, Database Management System. It helps us to manipulate files in folders, and as long as we learn the instructions that the DBMS recognizes, we can control the processing oUTF-8...
Posted by eyegraphix on Wed, 03 Nov 2021 22:45:14 +0530
mysql database master-slave configuration
This article will explain the master-slave configuration method of mysql database. After the master-slave configuration of mysql database, the backup of database and the separation of read and write can be realized, so as to improve the concurrency of applications. 1. Master-slave principle ThUTF-8...
Posted by Gorf on Thu, 04 Nov 2021 03:05:00 +0530