mysql sum count

In mysql, there are two functions: count () and sum (). Many of them are confused. From an English perspective, we can find that count is the number of statistics, sum is the sum of values and can only be numeric. In mysql, there are two functions:

Count () differs from sum () in MySQLFirst, create a table to illustrate the problem create table ' result ' (' name ' varchar () default NULL, ' subject ' varchar () default NULL, ' Score ' tinyint ( 4) Default NULL) Engine=myisam default

MySQL learning footprint record 10 -- Summary Data -- data used in this article, such as MAX (), MIN (), AVG (), SUM (), and COUNT () mysql> SELECT prod_price FROM products;+------------+| prod_price |+------------+| 5.99 || 9.99 ||

Title MySQL SUM () COUNT () is also in the work of the recordSUM () returns the number of columns and the total number of points such as a studentEg:select sum (obj) from table is definitely the sum of the numbers of the obj columns in the table

Requirements: Check out the average score of 2 and 2 people who fail.There are two types of query statements that are often used: The code is as follows Copy Code 1. Select Name,sum (Score =2; Look again Count

Difference between count () and sum () in Mysql Create table 'result '( 'Name' varchar (20) default NULL, 'Subobject' varchar (20) default NULL, 'Score 'tinyint (4) default NULL ) ENGINE = MyISAM default charset = utf8 Insert some data, Insert

Difference between count () and sum () in Mysql bitsCN.com First, create a table to describe the problem. Create table 'result '( 'Name' varchar (20) default NULL, 'Subobject' varchar (20) default NULL, 'Score 'tinyint (4) default NULL ) ENGINE =

After the avg (), count (), min () max (), sum () functions of mysql are familiar with the simplest SQL statements, do you think the cmd form is particularly appealing to tao Huan (yan )! Of course, we have a more intuitive and easy way to use

MySQL learning footprint record 10 -- Summary Data -- MAX (), MIN (), AVG (), SUM (), COUNT () bitsCN.com MySQL learning footprint record 10 -- Summary Data -- MAX (), MIN (), AVG (), SUM (), COUNT () Data used in this article mysql> SELECT prod_

First, create a table to describe the problem.Copy codeThe Code is as follows:Create table 'result '('Name' varchar (20) default NULL,'Subobject' varchar (20) default NULL,'Score 'tinyint (4) default NULL) ENGINE = MyISAM default charset = utf8