The table structure is as follows:
The code is as follows
Copy Code
Mysql> Show CREATE TABLE Userg;1. Row ***************************Table:userCreate table:create Table ' user ' (' ID ' int (a) unsigned not NULL
SQL tuning is primarily about reducing the number of consistent gets and physical reads.
COUNT (1) is compared with COUNT (*):
If your datasheet does not have a primary key, then count (1) is faster than COUNT (*)If you have a primary key, the
The table structure is as follows:Mysql> Show CREATE TABLE user\g;*************************** 1. Row *************************** table:usercreate table:create Table ' user ' ( ' id ' int (ten) unsigned not NULL AUTO _increment, ' name '
Tested under MySQL 5.6.MyISAM Engine:When creating a data table, MySQL generates 3 files, respectively (table: Test):TEST.FRM, Test. MYD, Test. Myi file,TEST.FRM is the table structure, Test.myd is the file that holds the data, Test.myi is the file
I. User table information
Ii. Conclusion
Use the query statement: Select count (1) from user; Use the explain statement to check whether the statement is indexed. the following result shows the query time of the statement.
Data Volume query
MYSQL row-to-column conversion and basic aggregate function count, used in combination with group by and distinct, countdistinct
The count function is often used in statistical queries. Here, the basic MYSQL row-to-column conversion and basic
Summary of differences between count (*), count (1), and count (col) in MySQL, mysqlcol
Preface
The count function is a function used to count records in tables or arrays. count (*) returns the number of rows to be retrieved, whether or not it
Mysql count details and function instance code, mysqlcount
Mysql count details
The count function is a function used to count records in tables or arrays. The following describes how to use the count function in mysql.
Count (*) returns the number
For details about how to use the count function in MySQL, mysqlcount
The count function is a function used to count records in tables or arrays. Here we will introduce the usage and Performance Comparison of the count function in MySQL.
Count (*)
Usage of the count function in MySQL
The count function is a function used to count records in tables or arrays. Here we will introduce the usage and Performance Comparison of the count function in MySQL. Count (*) returns the number of rows to be
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