MySQL

//Multi-table query: Get the latest data before you execute a multi-table querySELECT * from' Students ' st ' Right JOIN( SELECT * from (SELECT * fromGoutongWHEREgoutongs= ' asdf 'ORDER byTimeDESC　　) asGttGROUP bygtt.name_idORDER byGtt.goutong_

Before the interview was asked why to use the MySQL stored procedures, or the advantages of stored procedures. As a professional MySQL DBA. Must be mastered, surely. And I'm just ops, hahaha. At that time the answer was not good, and then tidied

one, MySQL error: Error (HY000): File '/var/www/xiaoyou/static/upload/import/20130427105733.csv.txt ' not Found (errcode:13)-Error when importing TXT file (LOAD DATA INFILE ' bj ' into TABLE bjpi fields TERMINATED by ', ' LINES TERMINATED by ' \ n '

Let's talk about the use of simple joins in detail below. First we assume that there are 2 tables A and B, and their table structures and fields are:Table A: Id Name 1 Tim 2 Jimmy

Most of the time we want to determine whether a record exists, if it exists, it will be updated, and will not be inserted! The usual practice is to write an IF Exist to make a judgment, but now MySQL gives us a more straightforward statement that is

Add dataWhen the primary key conflict is, choose how to DoInsert into table (id,name,age) value ("ddd", 45)On duplicate key update name= ' DDD ' age=45;The default has a PRIMARY KEY constraint and will not be inserted successfullyHowever, you can

Removing duplicate records Distinct example: SELECT DISTINCTUnion union query, merge the query results of 2 SELECT statements to use the knife all to ensure that the data is displayed (can display 2 times the same record)Usage (SELECT statement)

Storage EngineMyISAM InnoDB, most commonly usedcan be configuredDefault-storage-engine=innodb Configuring the default engineMyISAM These 3 together structure, data, index (a table consisting of these 3)Engine MyISAMEngine InnoDB1. Save the file in

Install (Deploy) method1) Yum installation (not high-demand occasions);2) Compile and install (General installation method);3) Camke installation method;4) Binary installation.Note: I study is still shallow, for the time being the MySQL single

This is a problem with MySQL character encoding because the MySQL default character encoding is Latin1It does not recognize Chinese, so garbled text will appear when reading query statementsSo that the query condition is incorrectSo we just need to

Today is the first time to contact MySQL, and hope to connect MySQL through C + +, a day of search down, a lot of benefit.Here is just a list of links to tutorials to prepare for a rainy future.1. Installation part: sudo apt-get install

Reprint Address: http://itlab.idcquan.com/linux/MYSQL/918330.htmlMySQL query does not use index RollupAs is known to all, increasing the index is an effective way to improve the query speed, but many times, even if the index is increased, the query

First, INNODDBThe InnoDB table is built on a clustered index, and the default level is Repeatable_read (repeatable read), which supports hot backup, which is not supported by other MySQL engines.Row-level locks are supported to handle a large number

Installing MySQL on Ubuntu is very simple and requires just a few commands to complete.1. sudo apt-get install Mysql-server2. Apt-get Isntall mysql-client3. sudo apt-get install Libmysqlclient-devDuring installation, you will be prompted to set a

Add Record:NOTE: The NULL keyword is combined with the auto_increment restriction to automatically assign a value to the field, the field must be full, and one by one corresponds; a single quotation mark for the character type;1

Although MySQL stored procedures, in general, will not be used, but in some special scenarios, there is still demand. Recently encountered a project that SQL Server migrated to MySQL, there are some SQL Server stored procedures that need to be

Creating a source table and inserting source dataDROP TABLE IF EXISTS ' score '; CREATE TABLE ' score ' ( int(one) not NULL auto_increment, 'class' varchar (255) default NULL, double default NULL, int( One default NULL, PRIMARY KEY (' id '))

Enter MySQL (mysql-u root-p) to view the current database character set (status;)At first it was latin1, so garbled.Vim/etc/my.cnfTwo nodes are added as

1. Build a database in MySQL test1Statement: CREATE DATABASE Test12. CREATE TABLE ExaminfoCREATE TABLE Examinfo (ID int auto_increment NOT NULL,Endtime datetime,Primary KEY (ID));3 Inserting data:INSERT into Examinfo values (' 1 ', ' 2011-4-23 23:26:

MySQL active/standby hot standby and mysql active/standby 1. Slave_IO_Running: No mysql> show slave status\G*************************** 1. row *************************** Slave_IO_State: Master_Host: 192.16.10.21