MySQL

/*************************************** ******************************* Author: Samson* Date: 04/01/2014* Test platform:* Linux ubuntu 3.2.0-58-generic-pae* GNU bash, version 4.2.39**************************************** ***************************

This article describes how to use the MySQL command to view how long the MySQL service has been started and run. Show global status like 'uptime '; The unit of the query result is seconds. Calculate the specific start time by yourself. The current

During the database table copy and backup operations, we should all know that there are two methods: select into from and insert into select? I will not talk about the differences and usage of the two methods here. If you need them, refer to the

This article analyzes the problem of slow query on the MySQL database server and puts forward the corresponding solutions. The specific solutions are as follows: Developers often find that they do not use indexed or limit n statements, which will

I would like to share several methods to improve MYSQL performance, which are not comprehensive enough. I hope you can add them! Please make a picture of the error! 1. database/table sharding Obviously, the unlimited growth of a primary table (that

This document summarizes the commands for viewing the MySQL character set. Commands include viewing MySQL database server Character Set, viewing MySQL database character set, character set of data tables and fields, and Character Set supported by

The InnoDB Engine of MySQL is configured with indexes and data cache pools. The LRU algorithm is used to maintain the cache hit rate. The sequence table list is used as the buffer pool. Each data node is called a block. This algorithm uses the dot-

ZookeeperThere is a mysql database table. The result of querying the last two pieces of data is as follows: This is the content in the original table:Idname1 ad2 jk3 tre 4 hgv This is the last two pieces of data to be queried (for the latest

InnoDB provides MySQL with a transaction security (ACID-compatible) storage engine with the capabilities of commit, rollback, and crash recovery. InnoDB locks row-level and also provides an Oracle-style non-locked read in the SELECT statement. These

This is the Fotolog experience. It is said that Fotolog has deployed 51 memcached instances on 21 servers and cached up to GB of content on 21 servers, this number is much larger than that of databases on many websites. The original Article is A

  The question was answered by Baidu five years ago. When I first saw this question, I had just been working for 21 days. Then, based on my own experience and Temporary Operation tests, I made a correct answer:

How to add innoDB to phpMyAdmin PhpNow (the free green Apache + PHP + MySQL environment package under Win32) finds that the database does not support the innoDB Engine by default. Many methods have been tried on the Internet. The following method

Requirement: copy the content of a field in one table to a field in another table. Implement SQL statement 1:Copy codeThe Code is as follows:UPDATE file_manager_folder f1Left outer join file_manager_folder f2ON f1.name = f2.name AND f2.parentId =

The format of the DATE value is 'yyyy-MM-DD '. Other formats are not allowed according to standard SQL statements. This format should be used in the WHERE clause of the UPDATE expression and SELECT statement. For example: MySQL> SELECT * FROM

CONVERT () provides a way to CONVERT data between different character sets. Syntax: CONVERT (expr USING transcoding_name) In MySQL, the conversion code name is the same as the corresponding Character Set Name. Example: Select convert (_ latin1

  I have encountered the problem of "mysql server has gone away" during development. It is assumed that the wait_timeout setting on the MySQL server is exceeded due to the absence of operation for a long time, the connection is eventually reclaimed

How to query the differences between where and having: Having clauses are similar but different from where clauses. They are all statements that set conditions. In the Query Process, aggregate statements (sum, min, max, avg, count) are executed

SQL sorting, grouping, and statistical commonly used statements: 1. Sort data in order Generally, all of your data really needs to be arranged in a certain order. The SQL ORDER BY statement can organize data in alphabetical or numerical ORDER.

  During the past few days, data statistics are performed. During the statistical process of database data, You Need To group data by specified days,   If you haven't found a good method before, retrieve the data and group it in the program.  

We know that MySQL does not support conditional indexes. What is conditional index? A conditional index is an index generated after a certain filter is performed on the index Column Based on the WHERE condition. Such indexes have the following