mysql explain extra

Explain can parse the execution of the SELECT statement, which is the "execution plan" of MySQL.One, type columnMySQL finds the desired line in the table. Include (from left to right, from worst to best): | All | Index | Range | Ref | Eq_ref | Const,

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 Explain here to do a comprehensive collation of the data. I. Grammar Explain For example: Explain select * from T3 where id=3952602; Two. Explain output interpretation +----+-------------+-------+-------+-------------------+---------+----

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

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

A lot of friends in the tuning with MySQL will certainly use the explain to see the execution of the SELECT statement, here is a brief introduction to the results of the meaning of the two columns.1 Type column The official saying that this column

A lot of friends in the tuning with MySQL will certainly use the explain to see the execution of the SELECT statement, here is a brief introduction to the results of the meaning of the two columns.1 Type column The official saying that this column

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