Database quiz question 2 and database quiz question 2
Questions on Century jiayuan Network
1. count the number of persons in each category (type:
Select type, count (type) from tab_user group by type;
2. Count the total score of five people:
Select sum (score) from tab_user;
3. Select the top three according to the score, and sort them in reverse order:
Select * from 'tab _ user' order by score des
Mysql quiz and mysql quiz
1. the user logon log table xes_user_login_logs is as follows:
(1) retrieve user IDs that have been logged on more than twice (SQL statement)
Select user_id from vvt_ceshi group by user_id having (count (user_id)> 1;
HAVING is like the WHERE condition, used to retrieve a dataset according to specified requirements. However, the WHERE clause is generally used to specify condit
Python quiz and python quiz
A colleague asked a friend a small question and question.
As I was learning python, I wanted to write this question in python to practice my hands and work hard, and I was inspired by my colleagues. I wrote the following code:
#! /Usr/bin/env python # coding = utf8i = 19j = 1for x in range (1, 21): print I *"", '* j + = 2 I-= 1for y in range (): # This sentence is purely for
The second issue of the NetEase Cloud Community award-winning quiz began! (The first phase of the event has ended: Artificial intelligence book Lottery!) )Welcome to participate in NetEase Cloud community, discuss issues, exchange ideas. We have prepared a number of technical field of hot books in this issue, to participate in the community of friends, will be sent in the form of a lottery.How to participate in Sweepstakes: 1. From now until March 19
650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M00/85/DE/wKioL1etMTKR6J7EAAJ3F9APqj8826.jpg "title=" 710-420.jpg "alt=" Wkiol1etmtkr6j7eaaj3f9apqj8826.jpg "/>The four-year-old Olympic Games are Rio in full swing, and Chinese Olympic athletes are vying for the highest glory of the Olympic Games. In this 8 months of national Carnival , in addition to the Chinese Olympic athletes refueling, applause, of course, there is a passionate prize quiz! P
test Linux without installing LinuxD. The stored content will be destroyed in a few minutes
When Linux is installed in a virtual machine running on a Windows system, which of the following statements is correct?A. The Linux partition is permanently created on the computer's hard driveB. Linux partitions are temporarily created on the computer's hard driveC. No Linux partition was created
Gnome,unity,kde is based on the underlying software to display the graphical interface?A. GrubB. X Serve
"Death Quiz" (Sola) the Otaku virus will create (%sola%runtime.txt) files and record the number of executions at the first time. When the cumulative number of executions reached 50, the virus will deadlock the computer, delete system-critical files, causing users to restart the computer, you will not be able to re-enter the system. Do not panic after the discovery of poisoning, to download a special kill software online. There have been a variety of n
You are have been given the job of forming quiz teams for the next ' MCA CPCI quiz '. There Are2*n students interested to participate and your have to form N teams, the each team consisting the two members. Since the members of the have to practice together and all the students want the their member's house as near. Let X1 is the distance between the houses of group 1, x2 be the distance between the houses
TopicIf you are a geography teacher with 35 students in your class, you want to take a quiz in the capitals of the U.S. state. Unfortunately, there are a few bad guys in the class, and you can't be sure that students won't cheat. You want to randomly adjust the order of the questions so that each paper is unique, which makes it impossible for anyone to copy the answer from someone else. Of course, it's time-consuming and boring to do it by hand. Fortu
system is consistent after the end of the transactionIsolated isolation: Things that are executed concurrently cannot see each other's middle stateDurable persistence: All changes made after the transaction is completed will be persisted, even if a catastrophic failure has occurred.58. What is data dirty read, Phantom Read, non-repeatable read?Dirty read: The rollback of a transaction is performed after reading to the modified but uncommitted transaction content. In other words, a dog forced to
would the Vectorize this code to run without all for loops? Check all the Apply.
A: v = A * x;
B: v = Ax;
C: V =x ' * A;
D: v = SUM (A * x);
Answer: A. v = a * x;
v = ax:undefined function or variable ' Ax '.
4.Say you has a vectors v and Wwith 7 elements (i.e., they has dimensions 7x1). Consider the following code:
z = 0;
For i = 1:7
Z = z + V (i) * W (i)
End
Which of the following vectorizations correctly compute Z? Check all the Apply.
and adds the functionality that some Web applications require. Unlike normal ApplicationContext, Webapplicationcontext can be used to handle theme styles, and it also knows how to find the appropriate servlet.67. What is the controller of the Spring MVC framework?The controller provides access to the application's behavior, typically through the service interface. The controller parses the user's input and translates it into a model that is presented to the user by the view. Spring implements t
1. The rules for Java identifiers are like thisIdentifiers consist of letters, numbers, underscores "_", dollar Sign "$" or the renminbi symbol "¥", and the first letter cannot be a number. That is, in addition to _ $¥ these 3 symbols, identifiers can only have numbers and letters, what parentheses, so that is not part of the identifier.You cannot use keywords and reserved words as identifiers.Identifiers do not have a length limit.String $;String Y2;String idfkd$fff;String ADKYDKJK;String _DJFK
allocation strategy, and briefly describe its principle
12345
轮询:默认的方式,按时间顺序依次分配weight:根据服务器权重进行轮询分配ip_hash:按ip的hash值进行分配,可以解决session保持url_hash:按访问url的hash结果来分配请求,使每个url定向到同一个后端服务器,后端服务器为缓存时比较有效fair:按服务器响应时长进行分配
12, crontab timing: In November, every day in the morning 6 to 12 points, every 2 hours to perform a/usr/bin/httpd.sh how to achieve
1
06-12/2*11*/usr/bin/httpd.sh
13, iptables prohibit IP 10.10.10.1 access to local 80 port
filter?Answer: The tee filter is used to send output to multiple destinations. If used for pipelines, it can copy the output to one file and copy the other to the screen (or some other program).[Email protected]:~$ ll/etc | NL | Tee/tmp/ll.outIn the example above, the LL output can be captured in the/tmp/ll.out file and also displayed on the screen.Q: Export PS1 = "[Email protected]:\ $PWD: What is this command doing?]A: This export command changes the login prompt to display the user name, the
a Windows system, which of the following statements is correct?A. The Linux partition is permanently created on the computer's hard driveB. Linux partitions are temporarily created on the computer's hard driveC. No Linux partition was created
Gnome,unity,kde is based on the underlying software to display the graphical interface?A. GrubB. X ServerC. Partitioning software
What is the role of the swap partition?A. Storing important software for Linux startupB. Storing files downloaded on the w
RM command do?A. Copying filesB. Deleting a fileC. Upload the file to the networkD. Put the file into the Recycle Bin
Which of the following commands can display the first few lines of a file?A. HeadB. TailC. Top
What is the command prefix that does not require login (toggle) to run the command as root, which can be root?A. sudoB. BerootC. NowD. Impossible
I forgot how to use the mkdir command, what should I do?A. In the Linux forum shouted, "Come on, do me a favor."B. Man mkdirC. Help mk
-text files. LCTT: When used to analyze a binary program that is inexplicably present on your system, you can find suspicious file access, which is useful for tracing the intrusion.Q: What is the function of the tee filter?Answer: The tee filter is used to send output to multiple destinations. If used for pipelines, it can copy the output to one file and copy the other to the screen (or some other program).
[Email protected] : ~$ ll /etc | nl | tee /tmp/ll. out
In the
guess 0-60 of the number ' read-p ' Please enter your price: "Aexpr $A +1 >/dev/nullif[$?-ne0]then echo "Don't tease me, just guess the Numbers" ipplefi}guess () { if[ $A -eq $NUM ] then echo "guessed right, is $num yuan" exit0elif[ $A -gt $NUM NBSP;]NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;THENNBSP;NBsp;echo "Hey, why don't you buy it at this price?" "ipple elif[ $A -lt $NUM ] then echo "too low and too low" NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;NBSP;IPPLENBSP;NBSP;NBSP;NBSP;NBSP;NBSP
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