MySQL

To find out the inefficient SQL statements in mysql, you can use EXPLAIN to analyze the inefficient SQL statements. However, before using EXPLAIN, you need to enable mysql slow query logs to use EXPLAIN, let's take a look. In the face of rapid

Mysql lock table is an optimization item for better processing of ultra-large loads. Next I will introduce some problems encountered by the mysql lock table mechanism and mysql lock table. To optimize mysql in high concurrency, it is necessary to

This article will introduce you to a innobackupex-1.5.1: fatal error: no innodb_buffer_pool_filename error solution. There are many MySQL backup methods, including mysqldump, mydumper, mysql_hotcopy, and innobackupex. today there is a problem in the

This article will give you a summary of the ORA-01994: GRANT failure: the password file is missing or the problem has been disabled solution, here is the main permission problem, the following are some solutions for GRANT failure. Errors that occur

There are several formatting functions in mysql, such as format, date_format, and TIME_FORMAT. Many of them do not understand them. I will give you a detailed example to illustrate the usage of these three functions. 1. FORMAT (X, D) Format the

In mysql, The concat function has a feature that a value of null is returned no matter how much content the second character has. This feature makes us feel inconvenient in the instance application, but we need to use other methods to solve this

By default, order by in mysql can only sort numbers and date types, but it does not seem to be useful for varchar sorted type sorting. Next I will introduce to you how to solve the varchar sort problem. Today, I found an interesting problem when

In linux, I encountered the prompt mysql prompts [Warning] Cant create test file xxx lower-test. If you encounter such problems, let's take a look at the solution. I think you must search for this title from seo/seo.html "target =" _ blank ">! You

There are many errors reported during the mysql import stored procedure. Today I have summarized two error messages and solutions. I hope this tutorial will be helpful to all of you. The following error is returned when I import a stored procedure

Below I will summarize some SQL statements about MySQL giving users database operation permissions, which makes it very convenient for me to authorize mysql users, these statements can only be operated by the root or super administrator. Syntax:

How is the difference between ifnull and nullif functions used in mysql? I thought it was actually reversed. Otherwise, let's take a look at the usage of these two functions. IFNULL (expr1, expr2) If expr1 is not NULL, the returned value of IFNULL

This article will introduce you to some problems encountered during the jump and continuation of the MySQL Stored Procedure cursor operation. Let's take a look at the solutions to this problem. Recently, this problem occurs. During the MySQL stored

Debugging is a basic skill that developers must master. If an error occurs in calling the sphsf-api, use $ cl-> GetLastError (). Let's take a look at it. When we use coreseek or sphek, if the function returns false when we call an api in a program,

The commands used for importing and exporting databases or data in mysql include the mysqldump and source commands, which have their own advantages and functions respectively, next I will introduce how to use mysqldump to export data and use source

The default maximum connection data of the mysql database is 100. If you want to modify the data, you can use either the set GLOBAL max_connections command or the MySQL configuration file my. ini or my. cnf search for max_connections = and modify it.

When saving or querying data, the system prompts Illegal mix of collations (gbk_chinese_ci, IMPLICIT) and (utf8_general_ci, COERCIBLE) for operation \ '= \'. here, we will tell you that the data you want to save and the character encoding in the

We use three different commands to update, delete, and save data in mysql. Next we will introduce how to save, delete, and update data in mysql. Insert statement Definition: Insert statement insert a data entry at a time Insert into links (name,

This article focuses on mysql write optimization. Here we will explain mysql's Innodb and MyISAM storage engines. I hope this article will help you. * Innodb_buffer_pool_size If Innodb is used, this is an important variable. Compared with MyISAM,

Mysql5.1 has the view function. The following articles will introduce some considerations for mysql views, creation, deletion, modification, and creation. I hope this article will be helpful to you. Create View In MySQL, the complete syntax for

Next let's take a look at the notes on MySQL index operation commands. This article includes the creation, deletion, modification, and viewing of mysql indexes. Mysq index type:Common Index, unique index, and primary index 1. Common Index The only