Use of SQL Statement - Database Operation

[select] SQL statement query join(left/right) two-table join/multi-table join //Multi-table Joint Survey: $sql = 'SELECT * FROM news LEFT JOIN (news_type, news_photo)ON (news_photo.n_id=news.n_id AND n_type=news_type.id)'; //Joint investigation of two tables: $sql = 'SELECT * FROM s LEFT JOIN sc ON s.sno=sc.sno'; Three Tables Joint Ch ...

Posted by gawrrell on Sun, 05 Jul 2020 17:37:13 +0200

Methods of type javascript String

1. Basic string inheritance methods valueOf(), toLocaString(), toString(), returns the value of the base string represented by the object 2. Character Method 1.charAt() returns the character that returns the given position as a single string var str = new String("tengtang") console.log(str.charAt(1)) //"e" Squar ...

Posted by jabbaonthedais on Sun, 05 Jul 2020 17:12:16 +0200

Principle and java implementation of inserting red and black trees

A red-black tree is a binary balanced lookup tree in which each node has a storage bit to represent the color of the node, either RED or BLACK.Red-black trees have the following properties: (1) Each node is red or black (2) The root node is black (3) If a node is red, both of its sons are black (4) For each node, all paths from that node to its ...

Posted by alin19 on Sun, 05 Jul 2020 16:54:33 +0200

javaSpring uses maven's initial build step java project

1. Modify in maven projectPom.xmlIntroduce dependencies on spring.<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com ...

Posted by rockintyler on Sun, 05 Jul 2020 16:37:42 +0200

Gui-2

Write a JFrame window, the requirements are as follows: 1. Place a JPanel panel in the NORTH area of the window. 2. JPanel panel places the following components: (1) JLable label, the label text is "interest", then on the right are three JCheckBox multi-choice buttons, the options are "badminton", "table tennis" ...

Posted by depojones on Sat, 04 Jul 2020 17:59:22 +0200

Aliyun CentOS7.3 Build LNMP Manually

** 1. Turn off firewalls and selinux --------------- ** Close Firewall [root@localhost ~]# systemctl stop firewalld.service selinux [root@localhost ~]# vim /etc/sysconfig/selinux Find SELINUX=enforcing and change enforcing to disabled [root@localhost ~]# setenforce 0 ** 2. Install nginx --------- ** wget download install ngi ...

Posted by antwown on Sat, 04 Jul 2020 17:42:46 +0200

Simple implementation of sector charts

Demo Address Main Code 1. Traverse the proportions of all sectors, calculate the start and end angles of each sector area, and then draw FanShapeLayer int max = 0; for (NSNumber * obj in self.angles) { max += [obj intValue]; } CGFloat startAngle = self.startAngle;// Start 0 represents the positive direction of the x-axi ...

Posted by markmil2002 on Sat, 04 Jul 2020 16:40:48 +0200

js native for high performance lazy loading (novice oriented)

Young brother is not talented, he made a simple lazy load to save moneyWindow.onscrollNumber of times to improve performance, designed function throttling and function anti-shake two modes, think of a better way to update later, also ask your friends to give more pointers!!:D Say nothing but code~~ 1. Simple lazy load ...

Posted by roustabout on Fri, 03 Jul 2020 17:47:06 +0200

Pure css tabs and drop-down menus

To tell the truth, this little trick is expected to be common now. I didn't pay much attention when I started. Until a project was used this afternoon, it reminded me that I developed it according to my own ideas, without referencing others, and felt quite accomplished. Ha-ha. The idea is simply to set the contents under the li list as absolu ...

Posted by Dasndan on Fri, 03 Jul 2020 17:37:38 +0200

MySQL Installation Configuration

Linux version: CentOS 6.5 64-bit 1. Download MySQL wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.20-1.el6.x86_64.rpm-bundle.tar 2. Decompression mkdir mysql cd mysql [root@localhost mysql]# tar -xvf mysql-5.7.20-1.el6.x86_64.rpm-bundle.tar mysql-community-embedded-devel-5.7.20-1.el6.x86_64.rpm mys ...

Posted by phpMitch on Fri, 03 Jul 2020 17:18:54 +0200