MySQL

Today, a friend of mine asked me a question through show processlist see a percent percent semicolon, for example:650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M00/4A/16/wKioL1QiOmbRjUExAAG-G9apoWw726.jpg "title=" 1.jpg " alt=

MySQL versionAlfa-Beta->gaGA represents production environment useMySQL Limitations1, do not complex transaction support, RR level, auxiliary next-key lock, you can meet the requirements of high consistency;2, really need materialized view, can

Yesterday, the test server restart, MySQL can not start normally, and then due to business needs to migrate the intranet database to the test server, in the restore Database times error is as follows:[Email protected]:~/sql$ mysql-uroot-p ' 1qaz2wsx3

1, WHERE clause in the query conditions are not equal to the number (where column!= ... ), MySQL will not be able to use the index2. Similarly, if a function is used in the query condition of the WHERE clause (for example: Where day (column) = ... ),

1. Query all  *select * from table_name;2. Query the specified column mysql> select myname from  zhuzhu;+--------+| myname |+--------+| zhang3 | |  li4    | |  zhang3 | |  li4    | |  zhang3 | |  li4    | |  zhang3 | |  li4    | |  zhang3 | |  li4   

Suppose there is now a table books:1. Duplicate table Structure 1.1 complete table structure with information such as primary key CREATE table new table name like book;  1.2 Only table structure, no primary key and other information CREATE table new

SELECT Fl.name,fvl.value,count ((Fvl.value)) n from Ps_feature_lang FL left joins Ps_feature_product FP on (fl.id_feature= Fp.id_feature) left JOIN Ps_feature_value_lang FVL on (fvl.id_feature_value=fp.id_feature_value) WHERE fp.id_product in

For a database-centric application, database optimization directly affects the performance of the program, so database performance is critical. In general, to ensure the efficiency of the database, to do the following aspects of the work:1, database

MySQL command line, you can modify the MySQL database password, the following for you to detail the MySQL command line, if you are interested, may wish to see.Format: Mysqladmin-u username-P Old password password new password1, add a password to

MySQL supports single-bidirectional, chain-cascade, real-time, asynchronous replication. During the replication process, one server acts as the primary server (master), and one or more other servers act as slave servers (Slave).Replication can be

First, view all databasesMysql> Show databases;+--------------------+| Database |+--------------------+| information_schema | | mysql | | performance_schema | | WMS |+----------- ---------+Among them, the first

Here is a list of the outlines that will be given in advance, as well as examples of what to do tomorrow:First, create a data table1) syntax for creating tables2) using PRIMARY KEY constraints3) using FOREIGN KEY constraints4) Using non-null

MyISAM Storage EngineOriginal http://www.cnblogs.com/villion/archive/2009/07/09/1893762.htmlMyISAM is the default storage engine. It is based on older ISAM code, but there are many useful extensions. Some features of the MyISAM storage engine:· All

Install Tpcc-mysql to do stress test, because Tpcc-mysql is BZR tool for version control, so first install BZR [Email protected]_backup/root] #rpm-UVH http://dl.fedoraproject.org/pub/epel/5/i386/ Epel-release-5-4.noarch.rpmretrieving

A strange thing happened to the recent payment business, after a transaction failed, call rollback and found that only the last SQL was rollback.Development looked for a long time, found that the network jitter, causing the first time to create a

Compared to other databases, MySQL is a bit different, its architecture can be used in a variety of different scenarios and play a good role, and understanding its design is a prerequisite for a good roleEvery time we think about MySQL's logical

Basic operations on MySQL Data Tables The following outlines are provided in advance, and details and examples are provided tomorrow: 1. Create a data table 1) Create Table syntax 2) use primary key constraints 3) use foreign key constraints 4)

Mysql development practice 8 Q: How many can you hold?Recently, the project has been heavily reliant on databases. I sorted out the eight representative questions that Mysql encountered during this period. The answers are also biased towards

MySQL stored procedure: Batch authorization for users To write these scripts, you need to write slow query logs into the database for ease of viewing. 1. because of the default mysql. the slow_log table uses the csv Data Engine and does not support

Differences between MySQL database char and varchar and suggestions for use, mysqlvarchar In a database, character-type data is the most frequently used, which accounts for more than 80% of the total database. Therefore, correct processing of