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
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 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
+----+-------------+-------+-------+-------------------+---------+----
Explanation of the usage of explain in mysql MySQLexplain
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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
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
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
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
MYSQL Tutorial: Explain usage MySQLexplain
I. SyntaxExplain Example: explain select * from t3 where id = 3952602;II. explain the output
Program code+ ---- + ------------- + ------- + ------------------- + --------- + ------- + ------ + ------- +|
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