Summary of SQL Database Language and Code Example

Summary SQL refers to Structured Query Language, which enables us to access it. data base SQL is a standard ANSI computer language. The SQL language is case-insensitive. SQL can be divided into two parts: Data Operation Language (DML) and Data Definition Language (DDL). SQL (Structured Query Language) is a grammar used to execute ...

Posted on Tue, 04 Jun 2019 13:17:38 -0700 by BKPARTIES

Myql operation usage (3)

view View is a virtual table (non-real), whose essence is to get dynamic data sets according to SQL statements and name them. Users can get the result set by using only the name, and use it as a table. SELECT * FROM ( SELECT nid, NAME FROM tb1 WHERE nid &g ...

Posted on Mon, 03 Jun 2019 21:39:41 -0700 by Cochise

MySQL Subquery Derived Table, Subquery Error

  From MySQL 5.7 ref: 13.2.10.8 Derived Tables   8. Derived Table Derived tables are expressions used to generate tables within the scope of a query's FROM clause. For example, a subquery in the FROM clause of a SELECT query is a derived table. SELECT ... FROM (subquery) [AS] tbl_name ... The [AS] tbl_name clause is required because ...

Posted on Sun, 02 Jun 2019 09:36:59 -0700 by supermerc

Introduction to Springboot Integration SpringDataJpa

Introduction to spring-data-Jpa First we know JPA(Java Persistence API), the Chinese name is Java persistence layer Api, a JDK 5.0 annotation or XML describing object-relational table mapping relationship, and the runtime entities Object Persistence To the database.It was created to integrate third-party ORM framework and establish unified ...

Posted on Sun, 02 Jun 2019 09:33:06 -0700 by ben14

docker swarm learning command collation

Docker swarm Initialize swarm manager and make network card address docker swarm init --advertise-addr 192.168.10.117 Force the deletion of the cluster, if it is a manager, you need to add force docker swarm leave --force docker node rm docker-118 View the connection token of swarm worker docker swarm join-token worker View the co ...

Posted on Fri, 31 May 2019 11:46:37 -0700 by bravo14

linux changes mysql data storage directory

Generally stored under / var/lib/mysql 1. View mysql's current data storage location [root@dlzx ~]# mysqladmin -u root -p variables |grep datadir Enter password: | datadir | /usr/local/mysql/data/ | [root@d ...

Posted on Mon, 27 May 2019 14:18:10 -0700 by EvilSupahFly

php file export full records

date: 2017-9-4 01:25:27 title: php file export full records Almost all of phper's needs come from the "management backstage", of which "file export function" is almost indispensable. After three years of phper, almost three years of this requirement has been followed. Recently, although I'm writing a server, since the little ...

Posted on Mon, 27 May 2019 12:35:55 -0700 by flyersman

Mycat Realizes Reading and Writing Separation of Mysql Database

I. overview Mycat's role in applications is described as follows: Mysql master is responsible for reading and writing for master library and Mysql slave is responsible for reading from slave library. In this way, programmers can only care about business code compilation, without worrying about load balancing of back-end database cluster, separa ...

Posted on Mon, 27 May 2019 10:56:43 -0700 by robert.access

An Example of SQL Statistics-mysql Implementation

1 /*Table structure for table `stuscore` */ 2 3 DROP TABLE IF EXISTS `stuscore`; 4 5 CREATE TABLE `stuscore` ( 6 `id` int(11) NOT NULL AUTO_INCREMENT, 7 `name` varchar(20) DEFAULT NULL, 8 `subject` varchar(20) DEFAULT NULL, 9 `score` varchar(20) DEFAULT NULL, 10 `stuid` varchar(10) DEFAULT NULL, 11 PRIMARY KEY (`id`) 12 ...

Posted on Sun, 26 May 2019 14:02:09 -0700 by p2grace

Mysql master-slave synchronous deployment

1. Create two virtual machines Master:172.10.12.248 Slave:172.10.12.249 2. Install mysql. Here I install binary MySQL 5.5 through script #!/bin/bash ####Author:lsy#### ####Time:2017/07/25#### ####One button installation Mysql-5.5 Edition#### #### Query whether mysql users exist#### user=mysql group=mysql #create group if not exists egrep ...

Posted on Sun, 26 May 2019 10:36:14 -0700 by sixseven