MySQL Tutorial SQL distinct delete duplicate records
How to use the DISTINCT keyword in MySQL to filter duplicate values in the result list of a SELECT statement
If you want to delete duplicate data while querying the data, you can use the DISTINCT keyword to filter the duplicate values, and then look at the distinct usage below.
SELECT DISTINCT column_name from table_name;
Let's take a look at a simple example where we have a list of cars. Each car has an ID, brand, type and color,
href= "Http://www.111cn.net" >class= "Btn-unfold hidden" href= "Http://www.111cn.net" >href= "Http://www.111cn.net"target=nt_phview> Aston Martin href= "Http://www.111cn.net"target=nt_phview> Aston Martin Db9class= "Btn-unfold hidden" href= "Http://www.111cn.net" >href= "Http://www.111cn.net"Target=nt_phview> Audi href= "Http://www.111cn.net"Target=nt_phview> Audi A6href= "Http://www.111cn.net"Target=nt_phv
, targeted to hair outside the chain).
In fact, better SEO way, is in the ranking optimization operation, according to the needs of users, do survey analysis statistics, and then cooperate with other customer needs, planning site program, will be SEO intention in the construction of the site (www.jianzhan001.com Media Production) in the process of good integration, So SEO do not tired, but also easy to achieve more ideal results, the above article Shing Peng referred to the services of customer
Java factory mode Java factory Mode
After reading so many explanations about the factory model, I still feel that this article is easy to understand and share with you.I. Introduction Ten years ago, there was a *** user who had three cars in his house, Benz, BMW, Audi, and hired a driver to drive for him. However, *** it is always strange to take a taxi: the Benz car was followed by the driver and said, "drive a Benz car !", When he got on BMW, he sai
. Introduction A decade ago, he had three cars in his house, Benz, BMW, Audi, and hired a driver to drive for him. However, it is always strange for the nouveau riche to take a taxi: the Benz car was followed by the driver and said, "drive a taxi !", When he got on BMW, he said, "kaibao carriage !", Get on with Audi and say, "Drive on AUDI !". You must say: this
Factory mode and abstract factory Mode
I. Introduction Ten years ago, there was a bad user who had three cars in his house (Benz(Mercedes-Benz ),BMW(BMW ),Audi(Audi) it seems that this man is more patriotic and has no Japanese car.) He also hired a driver to drive for him. However, when a taxi is used by a burst user, it always goes like this:BenzFollowed by the driver"Drive a Mercedes-Benz!",
car "leads" the rear of 20 cars with length Lincoln, 4 Cadillac, 4 Mercedes-Benz, 4 BMW, 4 Audi Q7 and other cars "arrogant" appearance, keep the dual-lane drive as much as possible, aligned with the open-lane Porsche. One of the dark Ferrari sports cars was very disobedient, fearing that the car in front of him had taken the limelight and moved freely between the neatly-arranged fleet, thus accumulating a lot of popularity for himself. In contrast
OPENJDK source code is not quite the same, it seems that the Oracle version of the core that something is not open source, F3 in I can not find it anyway, I am too lazy to find, but the principle is consistent, Here is the choice of openjdk.We review the JDK Dynamic agent, first of all the macro principles, I believe all understand that the use of the JDK dynamic agent is most common, at least for me is the spring AOP part, and is the AOP part of the declarative transaction part.A, define an in
First, a small storyTen years ago, there was an upstart who had three cars--benz Mercedes, BMW BMW and Audi, and hired a driver to drive him. However, the nouveau riche is always a strange ride: after Benz the car with the driver said "drive Mercedes!", after the BMW he said "drive a BMW!", the Audi said "open Audi car!". You must say: "This man is sick!" he said
How to arrange a multi-dimensional Array in the specified mode? [codePHP] Array ( nbsp; [0] nbsp; gt; nbsp; array nbsp; ( nbsp; how to arrange a multi-dimensional Array in the specified mode
[Code = PHP] Array
(
[0] => Array
(
[0] => 63
[Cate_id] => 63
[1] => 34
[Pid] => 34
[2] => original materials of Audi A6L New Type C6
[Cate_name] => original materials of Audi A6L New Type C6
[3] => 0
[
Core Role:--Instantiate the object and replace the new operation with a factory method--Will select the implementation class, the creation of key objects unified management and control, so that the caller and our implementation class decouplingCommon Application Scenarios:
Simple Factory mode:--The Simple Factory mode is also called the Static Factory mode, that is, the factory class usually uses static methods, and returns different object instances by accepting different parameters.--P
attribute, specify the name of the factory method and use the construtor-arg element to pass the method parameters for the factory method.
Detailed description of the Instance code: directory structure
Car. java
package com.coslay.beans.factory;public class Car {private String brand;private double price;public String getBrand() {return brand;}public void setBrand(String brand) {this.brand = brand;}public double getPrice() {return price;}public void setPrice(double price) {this.price = pr
Object (); 4 5 car.engine=engine; 6 7 Car.tire = tire; 8 9 return car; Ten One}Call Factory production objects:Var Audi = Createcar ("Four-engine", "Four-tire");To produce an Audi, a new object.To put it bluntly, the factory pattern is to encapsulate the method of creating objects in the function.In fact, when you use the instanceof operator to detect an instance of Audi:Alert (
of WordPressOf course, the Android Application of WordPress cannot be mentioned at the end. This is a project provided by the WordPress official development team. You can learn from the code to call XMLRPC (of course there are more excellent content ).Reprint: http://www.wandouhome.com /? P = 5440
Address: http://www.apkbus.com/android-13520-1-1.html
Android PDF Reader http://sourceforge.net/projects/andpdf/files/
Accounting tools OnMyMeans http://sourceforge.net/projects/onmymeans/develop
1. Create an application
Https://code.google.com/apis/console/
Set the corresponding application name to the URL address
Under API access
Oauth2_client_id, oauth2_client_secret, oauth2_redirect_uri
2. Download the Google client tool for PHP
Https://developers.google.com/google-apps/tasks/downloads? Hl = ZH-CN
3. Set config. php
Configuration
'Oss _ client_id '=> '6644545content. com ','Oss _ client_secret '=> 'zjcfno45452sb6hzgkcp3 ','Oss _ redirect_uri '=> 'HTTP: // e454545com/login/Gmail /',
4
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