plans, oracle introduces the concept of multi-column statistics in the 11g Database.
Selectivity: In this example, the value is 1/Unique.
We have a table named BOOKS with two columns named pai_id and rate_category. Let's take a look at the data distribution of these two columns:SQL> select distinct _id, rate_category, count (1) from books2 group by category _id, rate_category3 order by province _id;
Pai_id RATE_CATEGORY COUNT (1)---------------------
After setting up a website, the most concerned question is how many people have visited my website, that is, how much traffic is on my website. This can be continuously improved and optimized. Here will use Baidu's two statistical tools: Baidu Statistics and Baidu Webmaster to carry out analysis. With my own built based Hexo blog site: http://www.chenyufengweb.com. As an example.(a) Baidu statistics(1) Ente
What statistics can bring to you?
First, check the country and region of the subject;
Second, check the source of the questioner, for example, whether to use a search engine or a link to a link from another website.Third, view the operating system used by the Q A, display resolution, etc.Fourth, it is very popular to check which articles or pages on the website have a high renewal rate.
The following are 10 free site
Statistics
Statistic: A sample function without parameters. values can be calculated immediately based on the observed values of the sample.
The following is a simple random sample from the population and lists some common statistics. The following assumption is a sample, which is a matrix of a row and has been assigned a value in Matlab.
1.2.1SampleKMoment
Called a sampleKFirst-order moment. For a positi
PHP Questionnaire Survey Results Statistics, PHP Questionnaire survey statistics
Background:
Because of the specific work, I made a paper questionnaire, the main content of the questionnaire is to allow users to request the item (number A, A, b ...). ) to prioritize, so I get a good hundreds of copies similar to A>i>h>g>d .... and other results.
Goal:
Based on the user's sequencing results to quantify this
Empty the contents of the file and the size of the statistics file command, empty statistics
Empty the contents of the file:true > File name (or echo "" > file name)
Size of the statistics file:du-h--max-depth=1/usr/local/nginx/logs/* (* denotes all files in the logs folder)
Size of the Statistics folder: Du-sh fo
Oracle 12c Turn off statistics collection and enable statistics collection--Turn off statistics Col client_name for A60select client_name,status from Dba_autotask_client; Client_name STATUS------------------------------------------------------- ---------------------Auto Optimizer stats collection Enabledauto space Advisor
IOS traffic statistics and ios traffic statistics
During development, you sometimes need to obtain traffic statistics. The study found that the system network interface information is obtained through the getifaddrs function. The network interface information is contained in the if_data field. However, I only care about ifi_ibytes, ifi_obytes, it should be the nu
Use shell commands to analyze statistics logs and shell commands to collect statistics logs
When you need to collect user log information and analyze user behavior, you can use shell to conveniently retrieve a lot of data and place it in excel for statistics.
For example, for access with the address loadCustomProcess included in the
This article mainly introduces the Python text statistics function of the journey to the monkey with the word statistics operation, combined with examples of Python text reading, traversal, statistics and other related operations skills, the need for friends can refer to the next
This article describes the Python text statis
MySQL page access statistics and rankings, mysql access statistics rankings
MySQL page access statistics and rankings
Count the number of accessed pages to rank by resolution
SELECT CONCAT(`height` , '*', `width`) AS `resolution` , COUNT(CONCAT(`height`, '*', `width`)) AS `total` FROM `wifi_status_page` GROUP BY CONCAT(`height`, '*', `width`) ORDER BY `total` DES
Group function and group statistics, group function statistics
Grouping Functions
Grouping functions commonly used in SQL
Count (): Count
Max (): calculates the maximum value.
Min (): Minimum value
Avg (): calculates the average value.
Sum (): Sum
-- Count the number of people in the emp table select count (*) from emp; -- count the number of people who receive the bonus select count (comm) from emp; --
Grouping statistics query (Chapter Summary) and grouping statistics chapter summary1. Five grouping functions are provided in SQL: COUNT (), AVG (), SUM (), MIN (), and MAX.2. The group by clause can be used to GROUP data, while the HAVING clause can be used to filter the grouped data again.3. Multiple grouping fields can be created at the same time during grouping.4. Grouping can be used not only for entit
WinXP, Win7, Win8
Copy codeThe Code is as follows: 'indicate the source for reprinting original content and referencing the core part of the code.
Hard disk read/write statistics. vbs
If (Lcase (Right (Wscript. FullName, 11) = "wscript.exe") Then
CreateObject ("WScript. shell "). run ("% Comspec %/C" Chr (34) "mode con cols = 52 lines = 22" " Title hard disk read/write statistics. vbs By: FastSLZ PCEVA O
Mysql obtains statistics for a specified period of time. mysql statistics
Mysql obtains statistics within a specified period of time.
By year
SELECT count (*), DATE_FORMAT (order_info.create_time, '% Y-% m-% D') AS count_by_date FROM order_info WHERE DATE_FORMAT (order_info.create_time,' % y ') = '20140901' group by count_by_date ORDER BY NULL
Monthly
Tags: mysql row to columnI read a blog post very well, it is easy to understand after reading, the post address is: http://www.cnblogs.com/lhj588/p/3315876.htmlRecently I met a friend in the group and said, so record:Assume that the table name is T. There are six fields in the list p1,p2,p3,s1,s2,s3Now wantSum of S1 values when p1=100Sum of S2 values when p2=100Sum of S3 values when p3=100To create a table:CREATE TABLE ' t ' (
' id ' int (one) not null auto_increment,
' s1 ' int (one) default NU
$city_id =null Acquired_users$recommendphone=null Acquired_users$receivephone=null group1 Acquired_users_with_orders = distinct ( acquired_users_with_orders) ###### #去掉, the number of people who are not in the same city to take a taxi .... On the off-site vouchers, off-site taxi, in the city statistics when neglected. Acquired_users_with_orders$passenger_phone=null Acquired_users_with_orders$forjoin = acquired_users_with_ orders$city_id acqui
HDU 2017 string statistics, hdu2017 string statistics
String statistics
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission (s): 40487 Accepted Submission (s): 22532
Problem Description calculates the number of occurrences of numeric characters in a given string.
The Input data has multiple rows. The first row is an i
Introduction to statistics written by Japanese statisticians. It is interesting to introduce the most common statistical application scenarios, such as sampling surveys, random comparisons, and regression analysis. If you are interested in statistics and want to review statistics, you can take a look.Agree with the author's thought in the book: Statistical thinki
Do not search, output stack sequence statistics, search sequence statistics
1627: Time Limit for output stack sequence statistics: 1 Sec memory limit: 128 MB
Description
Stack is a common data structure, where n elements wait for the top side of the stack to enter the stack, and the other side of the stack is the output stack sequence. You already know tha
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