MySQL

TIPS is used for temporary tables in replication. We know that temporary tables have the following features: 1. At the SESSION level, once the SESSION is disconnected, it will be automatically dropped. 2. It depends on the default engine. If the

Method 1 for copying the table structure using command lines in mysql. only copy the TABLE structure to the new table create table new table select * FROM old table where 1 = 2 or create table new table like old TABLE 2. copy the TABLE structure and

When mysql 5.5 is installed, the memory usage is 00X00000000 and cannot be read. Solution: 1. stop mysql service cmd->: net stop mysql2. uninstall mysql with your preferred tool. 3. Delete the installation directory of mysql. Www.2cto.com 4. Delete

How to view MySql status-how does MySql view the number of connections and status and how does it enter the mysql command line? There is a bin directory under the mysql installation directory. first enter the directory with the command line, and

Solution 1: connect to the mysql database and report an error. mysql ERROR 2003 (HY000): Can't connect to MySQL server on 'localhost' www.2cto.com solution: Disable firewall, in linux, run the [root @ etl01 bin] # chkconfig -- list | grep-I iptables

The MyISAM engine uses B + Tree as the index structure. The data domain of the leaf node stores the data record address. It is the schematic diagram of the MyISAM index: Here there are three columns in the Table. Suppose we use Col1 as the Primary

Mysql obtains the insert ID. in MySQL, The auto_increment type id field is used as the primary key of the table. The general practice is to use the "select max (id) from tablename" method, but it is clear that this method requires consideration of

The SQL statement counts the number of people by age group. Java code www.2cto.com create table # t (Uname varchar (10), age int) insert # t select 'Ah', 19 union all select 'info ', 23 union all select 'baby', 31 union all select 'hour', 21 union

MySQL's "bug" on timestamp and mysqldump reproduce www.2cto.com. The problem that a colleague encountered when performing data dump is simplified as follows: 1. Create a table drop table if exists tb; create table tb (c timestamp not null default '20

Good mysql Union table multi-Table query. In previous queries, you can directly select * from tablea as a, tableb. as B where. cc = B. cc. today, I will share a novel way of writing, and the execution efficiency of hundreds of thousands of data is

Mysqls fragment operation description: www.2cto.com every time MySQL deletes a row of content from your list, this section of space will be left blank. A large number of delete operations within a period of time will make this blank space more space

Some Problems in mysqlslap output information: After adding debug-info to mysqlslap, in addition to the direct test results, some information about the test environment is also output. Www.2cto.com mainly includes: system time: time spent in kernel

ERROR 1201 (HY000): The problem of cocould not initialize master info structure today encountered an ERROR 1201 (HY000): cocould not initialize master info structure during MySQL master-slave replication. the reason for this problem is that you have

MySQL usage specification 1. Core Specification www.2cto.com 1. database operations are not required, such as md5 (), order by rand () 2. control the data volume of a single table a) a single table with a pure int value of no more than 1000 w B) a

MySQL DATA export and import tool: mysqldump (Database Backup command) backup database # mysqldump Database Name> Database Backup name # mysqldump-A-u username-p Password Database [size = large] Name> Database Backup name # mysqldump-d-A -- add-

MYSQL Username: root MYSQL Username: root3306 Chinese garbled Note: 1. delete the table with garbled characters first. change MYSQL configuration (INI file) 3. restart MYSQL Service 1. create database name; create database forStudy; 2. use an

Mysql master-slave Database Synchronization explanation master server settings 1. Create a replication user with the replication slave permission [SQL] mysql> grant replication slave on *. * to 'repl' @ '192. 168.1.22 'identified by 'repl'; 2. Edit

Mysql common options binlog-format can be set to STATEMENT (default), ROW, and MIXED. SUPER is required. It is not recommended to modify the binlog-format value when replication is in progress. Binlog-do-db (binlog-ignore-db, replicate-do-db,

In the hot standby server, switching SQL from the master node fails in the master node. When a Hot Standby server needs to be switched in time, the original Server Load balancer under the master node also needs to be switched to the new master

Mysql learning notes A Mysql and SQL syntax are almost the same, divided into the following categories. 1. Data Definition Language (DDL): create, alter, drop, etc. 2. Data Operation Language (DML): such as insert, modify, and delete 3. Data Control