connection type

Explain shows how MySQL uses indexes to process SELECT statements and join tables. Can help select better indexes and write more optimized query statements. Using the method, add explain to the SELECT statement: Such as: EXPLAIN SELECT ' surname ','

1 mysql> explain select count (id) from t_prehandle_zhigao_05 as zhigao where start_time> '2017-05-30 ';2 + ---- + ------------- + -------- + ------- + --------------- + ------------ + --------- + ------ + --------- + ---------------------------- +3

MySQL index and optimization Query An appropriate index can accelerate the query speed. There are four types: primary key, unique index, full-text index, and common index. Primary Key: It is unique and has no null value.Create table pk_test (f1 int

MYSQLexplain execution plan MySQLexplain BitsCN.com: Example: explain select * from test1 Description of the EXPLAIN column: Table: displays the data of this row about which table Type: this is an important column that shows the type used by the

Description of EXPLAIN in MYSQL MySQLexplain BitsCN. com1 mysql> explain select count (id) from t_prehandle_zhigao_05 as zhigao where start_time> '2017-05-30 '; 2 + ---- + ------------- + -------- + ------- + --------------- + ------------ + --------

Here we will introduce the EXPLAIN command in MySQL, and hope to help you explain how mysql uses indexes to process select statements and connect tables. It can help you select better indexes and write more optimized query statements. You can add

I have encountered some database problems during performance tests recently. I usually use slow query logs to find SQL statements with poor execution performance. However, I cannot find these SQL statements only, I have encountered some database

Explain shows how MySQL uses indexes to process SELECT statements and join tables. Can help select better indexes and write more optimized query statements. Using the method, add explain to the SELECT statement. EXPLAIN Explanation of the column:

Explanation of the Explain column: Table: Shows which table the data in this row is about Type: This is an important column that shows what type the connection uses. The connection types from best to worst are const, EQ_REG, ref, range, Indexhe,

Using the method, add explain to the SELECT statement before you can: Such as: Explain SELECT * FROM Test1 Explanation of the Explain column: Table: Shows which table the data in this row is about Type: This is an important column that shows what

The explain command in MySQL shows how MySQL uses the index to process SELECT statements and join tables. The information displayed by explain can help you select better indexes and write more optimized query statements.How to use 1.EXPLAIN:Add

Introduction:In the actual project development, because we do not know what is happening in the database when the actual query, database software is how to scan the table, how to use the index, so we can perceive onlyWhen the SQL statement runs, the

Explain shows how MySQL uses indexes to process SELECT statements and join tables. Can help select better indexes and write more optimized query statements.Using the method, add explain to the SELECT statement, such as:Explain select * from Statuses_

principles of MySQL index design 1. The index column of the search is not necessarily the column you want to select. In other words, the column that best fits the index is the column that appears in the WHERE clause, or the column specified in the

The index in the experimental Content single table uses 1. Build tableint, A1 varchar (A2), A3 varchar (+), A4 varchar (+), A5 varchar (a6), A7 varchar (+), A8 varchar (+), A9 varchar ( ))2. Write stored procedures Insert large data into tables//or

An index is a particular sort of algorithm for a particular MySQL field, such as a two-tree algorithm and a hashing algorithm, which is created by creating eigenvalues and then quickly finding them based on eigenvalues. And the most used, and is the

Explain shows how MySQL uses indexes to process SELECT statements and join tables. Can help select better indexes and write more optimized query statements.Using the method, add explain to the SELECT statement, such as:Explain select * from Statuses_

SQL Server Query Execution Plan AnalysisSource: http://www.sql-server-performance.com/tips/query_execution_plan_analysis_p1.aspxWhen you need to analyze the performance of a query, one of the best ways to see the execution plan for that query. The

Explain shows how MySQL uses indexes to process SELECT statements and join tables. Can help select better indexes and write more optimized query statements.Using the method, add explain to the SELECT statement:Such as: Explain select

How to use: Add explain before the SELECT statement, such as:Explain select * from user where id = 1Results:+----+-------------+-------+-------+------------------+---------+---------+-------+------+-------+| ID | Select_type | Table | Type |