MySQL

Learn a little bit of programming every day PDF ebook, video tutorial free download:Http://www.shitanlife.com/codeAfter grouping, count the number of record bars:SELECT Num,count (*) as counts from Test_a GROUP by num;The query results are as

MySQL decompression version: https://dev.mysql.com/downloads/mysql/ Initialize MySQLAfter unpacking, open the command line (CMD) into the MySQL bin directory input initialize mysql command: mysqld --initialize-insecure 2. Add

Experimental environmentVirtualized devices: Esxi6.0System: REDHAT7Database: MariaDB #操作与mysql相同The 18th chapter uses the MARIADB database management system.Learn 4 kinds of backup MySQL database (basic backup aspect no problem)First, the

First, error related1.MySQL ERROR 1005:can ' t create TABLE (errno:150) WorkaroundPossible causes:(1) Foreign key reference type is different, such as primary key is int foreign key is char(2) The column referenced in the primary table could not be

When I went to the interview today, the interviewer asked a question about MySQL's unique index, assuming that there was a unique index User_uni (name,age) and deleted the column age, what would happen?During the interview he said the column could

Create a database, delete a databaseCreate DATABASE Test charset UTF8 collate utf8_general_ci; set charset UTF8, proofing rules utf8_general_cidrop database test;Create a table, delete a tableCREATE TABLE Stu (ID int auto_increment PRIMARY

Database operationsNew data:Create database name Charset=utf8;To modify the database character set:ALTER DATABASE name Charset=utf8;Delete the database;drop database name;Querying the database currently in use;Select Database ();Query CREATE

In MySQL, each time a query is sent to the server, the following checks are performed before executing the statement: Does the user have permission to execute the statement? Does the user have permission to access the target data?

Delete from where not inch Select Max from Group by title)Just started using this statement to delete has not been successfulThen Baidu a bit, said is to create a temporary tableAs a result, the following actions are performedCreate a temporary

Consider the following query query.select name, course_idfrom instructor, teacheswhere instructor.ID = teaches.ID;The result is a relationship that has attribute name,course_id, and the property name in the result comes from the from property name

Rights Management1. Create an accountCreate a local accountCreate user ' luke ' @ ' localhost ' identified by ' 123 '; #mysql-uluke-p123Create a remote accountCreate user ' Luke ' @ ' 192.168.31.10 ' identified by ' 123 '; #mysql-uluke-p123-h

Index selectivity is the ratio of the number of results to the total number.expressed in SQL statements as:SELECT Count (*) from table_name WHERE column_name/select COUNT (*) from table_nameGenerally (for example, the book "SQL Tuning"), if the

DROP TABLE IF EXISTS ' frank_test ';CREATE TABLE ' Frank_test ' (' ID ' bigint () not NULL auto_increment COMMENT ' primary key ID ',' gid ' bigint DEFAULT ' 0 ' COMMENT ' base table ID ',' Frankly_code ' varchar (+) DEFAULT ' COMMENT ' Bill of

using third-party packages https://pypi.python.org/pypi/DBUtilsTAR-ZXVF *.tar.gz * Python3 setup.py build && python3 setup.py InstallIMPORTTIMEIMPORTPYMYSQLIMPORTTHREADINGFROMDBUTILS.POOLEDDBIMPORTPOOLEDDB, SHAREDDBCONNECTIONPOOL=POOLEDDB

MySQL database source code after compiling, start failure specific error log is as follows:2018-04-13 23:45:46 67547 [Note] Plugin ' federated ' is disabled./usr/local/mysql/bin/mysqld:table ' mysql.plugin ' doesn ' T exist2018-04-13 23:45:46 67547 [

What is a database?A database is a warehouse that organizes, stores, and manages data according to its structure.Each database has one or more different APIs for creating, accessing, managing, searching, and replicating the saved data.Classification

The content of this article: What is a view Create a View View View Changes to the View Deletion of views Data Operations for views Starting Date: 2018-04-13 What is a view: A view is a virtual table

1. Create a userCREATE USER 'Dingyingsi'@'localhost'Identified by 'dys123';//Create the user on this computerCREATE USER 'Dingyingsi'@'%'Identified by 'dys123'; The user created can connect to the computer remotely2. AuthorizationGrant Select,Insert,

1. Inserting a single row of dataINSERT into table_name SET= value 1,= Value 2,= value N;INSERT into T1 SETId=1,Name= ' Zhangsan ',sex= ' F ';2. Inserting multiple rows of dataINSERT into table_name[(Field 1, Field 2, field N)]VALUES(value 1, value 2

CREATE TABLE IF not EXISTS subscribers (SubscriberId int not NULL primary key,Rateplan varchar (6) Not NULL,Monthlyfee Float not NULL,Market varchar (TEN) is not NULL,Channel varchar (6) Not NULL,StartDate Date Default NULL,Stopdate Date Default