how to count rows in mysql

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

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 '

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

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

Some time ago, Era shared with you a Mysql database repeat detection function. For how to use this function, you can move to "Repeat detection function when mqsql data is stored in the database-php". today we will introduce two methods to count the

The convenient way to count the total number of rows in the query result in MYSQL saves the keyword count (*) bitsCN. comMYSQL: SQL _CALC_FOUND_ROWS After checking the manual, we found that this keyword is used to count the total number of results

After checking the manual, we can find that the SQL _CALC_FOUND_ROWS keyword is used to count the total number of results that meet the filtering conditions (not limited by Limit, if you are interested, you can learn the MYSQL Keyword: SQL

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

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