MySQL

I. insert and replace Both insert and replace statements insert new data into the table. The syntax of these two statements is similar. The main difference between them is how to process repeated data. 1. General insert usage The insert statement

Linux forgot mysql password retrieval method today we mainly talk about how to handle linux forgot mysql password. Below are five methods for restoring linux forgot mysql password. How to retrieve the password of the linux forgot mysql tutorialToday,

If the on duplicate key update is specified at the end of the INSERT statement, and DUPLICATE values appear in a UNIQUE index or primary key after the row is inserted, the old row UPDATE is executed; if the unique value column is not duplicate, a

The principles of SQL injection and the Measures to Prevent SQL Injection finally provide a php instance to show you how to prevent mysql injection and some common solutions in the future. Next we will write an introduction to SQL anti-injection and

SQL subquery, multi-Table query, and joint Query Subquery, multi-Table query, and joint QueryThese three concepts are interpreted slightly differently in different SQL versions, roughly as follows: JoinYou can check related SQL documents or buy a

SQL Tutorial: SQL SELECT DISTINCT instance tutorial This chapter explains how to select discrete speech.Select different declarations in SQLIn a table, some columns may contain duplicate values. This is not a problem, however, sometimes you want to

This article will share with you a good tutorial on configuring Linux MySQL master-slave Replication (Replication) (MySQL Data Synchronization). Thank you for your reference. MySQL is an open-source relational database system. Replication is a

This article introduces how to use group by sorting in mysql to obtain the most recent records in a record group. For more information, see. Mysql group by: sorts the records with the largest time in each record. Test SQL Create table if not exists '

Duplicate entry... for key... cause of error: this error occurs because the unique value of the primary key is repeated. This error is reported once the unique value of the primary key is repeated during database modification and insertion, if

Live is a good database management tool. The following describes how to import mysql Data into hive. For more information, see. The following is an instance that imports data from mysql into hive. -Hive-import indicates importing data to hive,

In the past, CodeSmith or dynamic software was often used to generate relevant database access code (not like to use Persistence frameworks). CodeSmith's support for Chinese characters was poor and the new version 6.5 was downloaded, the description

Does MySQL 5.1 storage programs and functions work for replication? Yes, the standard behavior executed in the storage program and function is copied from the master MySQL server to the slave server. Can the stored programs and functions created on

Today I saw the MySQL date function, which is a lot of useful. Here I only stick two parameters that are not easy to remember. (Refer to MySQL 5.1 reference manual) DATE_ADD (Date, INTERVALExpr Type) DATE_SUB (Date, INTERVALExpr Type) These

The following articles mainly introduce the disadvantages of MySQL indexes and the actual operations of MySQL indexes, which deserves our attention, we may not know that using indexes too much will cause abuse. Therefore, MySQL indexes also have

Case DescriptionDuring the running of the scheduled script, it is found that when the SQL statement for backing up the table and the SQL statement for deleting some data in the table run simultaneously, mysql will detect the deadlock and print the

System: Ubuntu 10.10Mysql source file: mysql-5.5.8.tar.gzInstall required tools: cmake, GNU make, gcc, Perl, libncurses5-dev, bison (optional), chkconfigNote:1. There are several bugs in the official source code from, which were manually modified by

MySQL uses the EXPLAIN statement to EXPLAIN the usage of Memory Ram (Memory) and CPU. MySQL 5.0.37 and later support MySQL Query Profiler. You can check the time when the SQL statement runs, and check the CPU/Memory usage. During the process, the

ThereforeCopy codeThe Code is as follows:Create_time datetime default now ()It is impossible to set the default value.The alternative is to use the TIMESTAMP type instead of the DATETIME type.CURRENT_TIMESTAMP: When I update this record, this field

When an slave server is connected to the master server, it notifies the master server of the last successful update location read from the server in the log. The slave server receives any updates from that time, blocks them, and waits for the master

I. SQL Quick StartThe following is an important quick reference for SQL. For SQL syntax and features added to standard SQL, please query the MySQL manual.1. Create a tableA table is one of the most basic elements of a database. Tables and tables can