MySQL

Work with statistics December call records, statistics number dialed number, but the problem in a number can be dialed multiple times, each may or may not be connected, if the call Number Caller field group by group COUNT (*) after the number of

The Date_format () function is used to display date/time data in different formats.GrammarDate_format (Date,format) The date parameter is a valid day. format Specifies the date/time in which the output is formatted.The formats you can use are:

MySQL is only allowed to log on localhost by default, and if you want to manage via Telnet, you need to modify the appropriate permissions.First: Turn on port 3306 on the host where MySQL is located, or turn off the firewall.Service iptables Stop #

Common operations for MySQLCreate the database User: "Create user ' username ' @ ' localhost ' identified by ' PASSWORD ';Delete database User: Delete from user WHERE user= "username" and host= "localhost";Authorization to User: Grant all privileges

Create a Custom Function:1 DELIMITER $$2 3 Use ' dressv_website ' $$4 5 DROP FUNCTION IF EXISTS ' fn_queryrelation ' $$6 7CREATE definer= ' sa ' @ '% ' FUNCTION ' fn_queryrelation ' (Areaid int,relation TINYINT (1)) RETURNS VARCHAR (4000) CHARSET

Mysql:cannot Delete or update a parent ROW:A FOREIGN KEY constraint failsThis could be because MySQL set the Foreign Key association in InnoDB, causing the data to not be updated or deleted. You can avoid this situation by setting the

http://blog.csdn.net/config_man/article/details/6123191Development environment: Windows XP Professional SP3, VS2008, Winform, MySQL5.0, MySQL.Data.dll 6.2.3.01. Read a picture from your hard disk, convert it to a stream, and store it in this BLOB

1. Create a stored procedure1 Create procedure Proc_name () 2 begin 3 SQL; 4 EndSQL executes the code at a fixed value, for example, inserting the current time into the table: INSERT INTO Table VALUES (now ()), and then execute the stored procedure

First, MySQL IntroductionMySQL is an open source small relational database management system, developer for Sweden MySQL AB, after the acquisition of the MySQL Ab,orance Company acquired Sum, so the current MySQL project by Orance Company is

Adjust the MySQL run parameters, modify the/etc/my.cnf file to adjust the MySQL run parameters after restarting MySQL, after the MySQL4 version, a part of the internal variables can be set in the MySQL runtime, but the restart of MySQL is

today started to install MySQL, originally to the official website to download the installation package to install, but after installation but can not use, is expected to configure it, search the Internet very much information, the result or failure.

Network traffic is normal after pinging and route, and local connections on the MySQL machine are found to be fast, so network problems are largely excluded. Once also encountered such a problem, but later on I do not know how suddenly good, this

Mysql> show Processlist;Mysql> Show status;Mysql> Show status like ' Slow_queries ';Mysql> Show status like ' threads_created ';Mysql> show engine InnoDB status\g;Mysql> show global status like ' table_locks% ';Mysql> Show status like '%lock% ';=====

1. Create a tableCREATE TABLE Table name (ID int unsigned NOT NULL Auto_increment primary key,Field column type NOT null default ' ',......Field column type NOT null default ' ') engine MyISAM charset UTF8;2. Modify the tableAdd Columns:ALTER TABLE

Mysql master Replication The customer needs high availability in the project, and the database is a key part of high availability. I have studied the high availability of many mysql instances, using mysql cluster and mysql master-slave master-master

MySQL (10)-date functionsDate and Time Functions (1) functions for obtaining the current date and time CURDATE () and CURRENT_DATE () functions to obtain the current date Select current_date (), curdate (), curdate () + 0;   Curdate () + 0 indicates

MySQLInnoDB lock mechanism (1) MySQL InnoDB has four types of locks: Shared locks (read locks, S locks), exclusive locks (write locks, X locks), intention shared locks (IS locks), and intention exclusive locks (IX locks ). The shared locks and

Usage of mysqlhavingHaving usage Having clauses allow us to filter various data After grouping. where clauses filter records before aggregation, that is, before group by and having clauses. The having clause filters group records after

MySQLServer alarm script MySQL Server email alert Implementation Method: The system's load and session are used to determine whether the system's current load is too high. If the load is found to be too high, an email alert is triggered (of course,

MySQL batch Delete tablesDuring job debugging, overview created a cron scheduled task that is executed once every minute. A table name with time information is generated every minute and you forgot to delete the scheduled task, currently, there are