MySQL

The database input Chinese is easy to appear garbled? (garbled problem Source: seehttp://blog.51cto.com/12042068/2115021)WORKAROUND: 1. Specify the default encoding UTF8 when building the table.                CREATE TABLE table_name (column_name

1.mysqld:can ' t create directory ' D:\mysql\data\ ' (OS errno 2-no such file or directory)Change the table of contents to a backslash2.MySQL Landing ErrorTo change the My.ini file:#sql_mode =no_engine_substitution,strict_trans_tables This

--Create a test tabledrop table if EXISTS t_passwd_2;CREATE TABLE T_passwd_2 (Pass1 varchar (64));--Encrypt the ID numberINSERT into t_passwd_2 values (Hex (aes_encrypt (' 22230119771011001X ', ' [email protected]# ')]);--The way the database is

Directly on SQL: Method one:Delete fromRoutewhereIdinch(Selectb.ID from(Select * fromRoute AwhereId<>(Select min(ID) fromRoutewherePayment_type=0 andPoint_start=A.point_start andPoint_end=a.point_end)) b);Question: a route table. Now you need to

MySQL Database syntax-multi-table query exercise oneYun ZhengjieCopyright Notice: Original works, declined reprint! Otherwise, the legal liability will be investigated.This blog mainly describes the foreign key constraints of multi-table queries,

For a large table of tens, now it may be more than billions of data, many people first reaction is a variety of segmentation, results are always more effective, perhaps it is our optimization sequence is incorrect. Let's talk about how the order of

What is a primary keyEach row in the table should have a column (or set of columns) that uniquely identifies itself. The columns that assume the role of identity are called primary keys .Any column can be a primary key, as long as it meets the

1. Download MySQL Resourceswget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm2. Installationyum -y install mysql57-community-release-el7-10.noarch.rpm3. Install the MySQL serveryum -y install mysql-community-server4.

MYSQLD is the MySQL server.Configuring the server.The MySQL server, mysqld,has Many command options and system variables that can is set at Startop t configure its operatio N.To determine the command option and system variable values used by the

Waiting to be written ~Explain:SELECTCase-------------IfWhen the sex= ' 1 ' then ' Male '-------------sex= ' 1 ', the return value ' male 'When the sex= ' 2 ' then ' female '-------------sex= ' 2 ', the return value ' female 'else 0 return ' other '-

1) Prepare test data: Build a table and insert test data in bulk by writing scripts.[email protected] scripts]# cat ceshi.sh#/bin/bashPath= "/usr/local/mysql/bin: $PATH" #定义mysql命令所在路径Myuser=root #定义数据用户名Dbpath=/server/backup #定义数据备份目录mypass=xiwei199

The table structure is as follows, the article has only 690 articles.Article table article (id,title,content)Tag table tag (tid,tag_name)Label Article intermediate table Article_tag (id,tag_id,article_id)One of the labels for the TID is 135, and the

First, common SQL statements1. Create a databaseCreate DATABASE test;2. Deleting a databasedrop database test;3. Using the DatabaseUse test;4. Create a data tableCREATE TABLE Sys_role (ID int (4) Not null primary key,Available char () NOT

Code for custom functions:drop FUNCTION IF EXISTS fn_hrstaffbase_getnamefromidcard Delimiter// CREATE FUNCTION Fn_hrstaffbase_getnamefromidcard (a VARCHAR ()) RETURNS VARCHAR () Begin Return (SELECT staff_ name   from hr_staff_base where idcard =

To create an index:ALTER table ADD INDEX ();>alter TABLE ' table_name ' ADD PRIMARY KEY (' column '); Add primary key (primary key index)>alter TABLE ' table_name ' Add unique (' column '); add unique (unique index)>alter TABLE ' table_name ' Add

HBase1, HBase for the query, it by organizing the memory of the machine to provide a large memory hash table, it needs to organize its own data structure, the table in HBase is a physical table, rather than a logical table, the search engine uses it

First, MySQL master-slave introduction MySQL master-slave is also called replication, AB replication. Simply speaking is a and b two machines from the back, write the data on a, the other B will follow the writing data, both data real-time

Installing PIP3 install Pymysql on the cmd command lineIf the installation is successful, the database can be pycharm and checked in the operation.Import pymysql# Module # CREATE link conn=Pymysql.connect (Host='127.0.0.1', Port=3306, the user='Root'

Log classification:One, error log.1, the configuration in the configuration file is:log-error= "Desktop-igoodful.err", view the parameters of the key value pairs: Show variables like ' log_error ';Two, binary log.Three, slow query log.1, slow query

This problem occurs after installation if you have not set it. When you turn on your computer, MySQL will start it on its own. (Click on the MySQL logo at the bottom of System preferences to view it). It should be the latest version of MySQL that