explain mysql

EXPLAIN is used to return a row of information for each table in the SELECT statement. Tables are listed in the order they will be read by MySQL during query processing. EXPLAIN is used to return a row of information for each table in the SELECT

MySQL execution Plan explain detailed 2015-08-10 13:56:27Category: MySQLThe explain command is the primary way to see how the query optimizer decides to execute a query.This feature has limitations and does not always tell the truth, but its output

The explanation of mysql explain is clear.Of With the help of explain, you will know when to add an index to the table to use the index to search for records so that select can run faster.If the index is not properly used, you can run analyze table

The explanation of mysql explain is clear.Of With the help of explain, you will know when to add an index to the table to use the index to search for records so that select can run faster.If the index is not properly used, you can run analyze table

Transferred from: http://www.cnblogs.com/magialmoon/archive/2013/11/23/3439042.htmlMySQL official manual description of the explain naming document: Https://dev.mysql.com/doc/refman/5.7/en/explain-output.html#explain_select_typeThe recent slow

Say 工欲善其事, its prerequisite. Today we will briefly introduce the next explain.Content navigation Id Select_type Table Type Possible_keys Key Key_len Ref Rows Extra Environment ready MySQL

Explanation of the usage of explain in mysql MySQLexplain BitsCN.com The explanation of mysql explain is clear.Of With the help of explain, you will know when to add an index to the table to use the index to search for records so that select can run

[MySQL Notes] SQL optimization tool-explain the output format of the explain command If you have experience using MySQL, you may encounter slow SQL queries in your project. In some scenarios, you can easily locate the problem (for example, when a

If you put the keyword explain,mysql in front of the SELECT statement, it explains how it handles the Select, providing an order about how tables are joined and joined.Each output row of the explain provides information about a table, and each row

The EXPLAINtbl_name or: EXPLAINSELECTselect_optionsEXPLAIN statement can be used as a synonym for DESCRIBE. It can also be used to obtain information about the SELECT statement to be executed by MySQL. The syntax of EXPLAINtbl_name is the same as