1. Equivalent connection
Principle: form a large logical table with multiple single tables.
Grammar:
select * from Table A, table B where table A. primary key = table B. foreign key and query condition
select * from Table A, table B where Table A. primary key = table B. foreign key and C. primary key =B. foreign key and query condition
Two. Internal connection
First judge, then connect.
The result of internal connection is the same as the result of equivalent connection.
Syntax: two tables
select *
from Table A inner join table B
on Table A. primary key = table B. primary key
whe...
queue The main principle is first in first out (excepted).
The difference between basic methods
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Add data:
add Add a metarope and throw an IIIega ISlabEeplian exception if the queue is full
put Add an element if the queue is full, then block.
offer Add an element and return to true. If the queue is full, then return to false.
Remove data:
remove Remove and return the element at the head of the queue if the queue is empty, throw ...
Media query
What is media query?
Media queries allow us to set CSS styles for device displays based on their features (such as viewport width, screen scale, device orientation: horizontal or vertical). Media queries consist of media types and one or more conditional expressions that detect media characteristics. Media features that can be used in media queries are wIdth, height and color (etc.). Using media queries, you can customize the display effect for certain output devices without changing the content of the page.
1、Media query operation mode
The actual operation is: ask the device (c...
Towards end-to-end reinforcement learning of dialogue agents for information access
KB-InfoBot
In the multi-round dialogue model interacting with the knowledge base, the symbolic query statement is abandoned and the soft posterior distribution is used in the knowledge base to find the most probable information.
du -ah –max-depth=1 This is the result I want a to show all the files and folders in the directory (excluding subdirectories), h to be human-readable, and MAX-depth to be directory depth.
duThe command is used to see the size of disk space occupied by a directory or file. Common options are: Du -sh
Functions of du: `du` reports the amount of disk space used by the specified files and for each subdirectory(of directory arguments). with no arguments, `du` reports the disk space for the current directory.
Obviously, unlike DF, it is used to see the size of disk s...
When someone tells you that you can live forever, he must be lying to you. Baidu Bidding Package Year is so, let’s talk about what is Bidding Package Year, and Bidding Package Year fraud.
Believe that many enterprises have received similar calls, that is, the so-called “Bao Nian Bidding”, the other side of the idiom is what Baidu Bidding by click, burning money and so on, and for Bao Nian Bidding, you only need to pay a fixed amount of money every year, no matter how visitors click, you will not spend additional money. cutRemember, thi...
First, we introduce two key word price adjustment methods, and then introduce some basic principles of price adjustment.
First, single word price adjustment, using the “promotion live” tool in the bidding account.
This problem is often used in mobile version.
<div class=”sousuo”> <input type=”text” placeholder=”Please enter the keyword “id=” sousuo of the title of the article. onkeydown=”entersearch()”/> </div>
css:
.sousuo {
width: 94%;
height: 3.5rem;
margin: 1rem auto;
}
#sousuo {
display: block;
width: 100%;
padding-left: 10%;
background: #f2f2f2;
height: 3.5rem;
border: none;
outline: none;
border-radius: .5rem;
background-image: url(../images/Icon_sousuo.png);
backgr...
