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about Index_hintIn the MySQL query statement, you can specify index_hint to tell the optimizer how to use the index, which can be consulted in detail hereIndex_hint: Use {index| KEY} [for {join| ORDER by| GROUP by}] ([index_list]) | IGNORE {

This article will detail the cause of MySQL garbled and the specific solutionWhy MySQL is garbledTo understand why garbled, we have to understand: from the client initiated the request, to the MySQL storage data, and the next time from the table to

MySQL command line when executing a multi-line command, if the command entered in front of an error, is unable to return the modification, but can be input \c to cancel the front input, but at this time if the front input a lot of things, the direct

Because a large number of changes are often performed on mysql databases, such as modifying fields, adding or deleting indexes, we put these operations into SQL statements, and then log on to mysql to access Because a large number of changes are

MYSQL Quick Start: MYSQL command line instructions http://www.bkjia.com/database/201212/173868.htmlMYSQL Entry 2: Search Using Regular Expressions http://www.bkjia.com/database/201212/173869.htmlMYSQL Entry 3: Full Text Search

An interesting thing was found during the recent writing process. Mysql procedure has its own unique processing method when passing parameters. For example, if the parameter is defined as an int, the result is null.Mysql procedure runs

MySQL command listView code 1 List of all MySQL commands: 2 Note that all text commands must be first on line and end with ';' 3 ? (\?) Synonym for `help'. 4 clear (\c) Clear the current input statement. 5 connect (\r) Reconnect to

MySQL Study Notes 01 _ basic database knowledge, mysql Study Notes01_1 mysql database Start and Stop Start cmd with ; Enter net stop mysql to stop mysql service; Enter net start mysql to start the mysql service; Enter mysql-u root-p and press

Because we often perform a lot of changes to the mysql database, such as modifying fields, adding or deleting indexes, we put these operations into SQL statements and then log on to mysql, execute this SQL file using source. In order to keep

MYSQL Getting started: MYSQL command line commands that can be used to describe bitsCN.com MYSQL Quick start: MYSQL command line instructions Related links: MYSQL: Basic operations Http: // database/201212/173868 .html MYSQL 2: use regular

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This article mainly introduces the ultimate solution to the garbled problem in MySQL, including encoding conversion and SQL data import and export, which is extremely powerful. we strongly recommend this excellent translation! For more information,

Explain can analyze the execution of select statements, that is, the execution plan of MySQL. The type column MySQL finds the required rows in the table. Including (from left to right, from worst to best): | All | index | range | ref | eq_ref |

MySQL Condition Optimization example. Not all HAVING conditions can be incorporated into the WHERE condition. Only when the GROUPBY condition or clustering function does not exist in the SQL statement can we MySQL Condition Optimization example. Not

IntroductionOptimizing SQL is a common task of DBA. How to optimize a statement efficiently and quickly is a common problem for every DBA. In my daily optimization work, I found that many operations are essential in the optimization process. However,

MySQL basics 06 data type (6) type conversion, mysql Data Type1.Cast () Usage In MySQL, cast (value as target type) syntax can be used for conversion of most types.   Cast must be followed by left parentheses: Mysql> select cast (123 as char ); + ---

Implicit MySQL conversion and implicit mysql Conversion   Implicit conversion rules The implicit conversion rules in the official documentation are described as follows: If one or both arguments are NULL, the result of the comparison is NULL, should

A MySQL bug about exists, MySQLexistsbug Today, I encountered a strange question about exists. The first statement is as follows: SELECTcount(1)FROMAPPLY tWHEREEXISTS (SELECTr.APPLY_IDFROMRECORD rWHEREt.APPLY_ID = r.APPLY_ID); Result: 89584 The

1. Explain extendedselect... decompile the execution plan into a SELECT statement and run showwarnings to obtain the query statement optimized by the MYSQL optimizer. 2. explainpartitionsselect... information contained in the explain execution plan

I met a strange question about exists today. The first statement is as follows: Select count (1) from the APPLY t WHERE EXISTS ( select r.apply_id from record R WHERE t.apply_id = r.apply_id ); The resulting results are: 89584 The