Programmer Think

Source code acquisition: download from "resources" on the blog home page! Project significance: Since the reform and opening up, China's tourism has developed rapidly, but comparatively speaking, the breadth and depth of China's tourism development are far from meeting the needs of economic development and the improvement of peopl ...

32 please send the last of all employees in the employees table_ Name and first_name is spliced together as name, separated by a space in the middle select concat(last_name,' ',first_name) from employees; Parsing, two string connection methods: mysql CONCAT(str1,str2,...) and CONCAT_WS(separator,str1,str2,…) 33 table building crea ...

1.Mybatis Environmental Science: JDK 1.8Mysql 5.7maven 3.6.1IDEA 2. Introduction 2.1 what is MyBatis MyBatis is an excellent persistence layer frameworkMyBatis avoids almost all JDBC code and the process of manually setting parameters and obtaining result setsMyBatis can use simple XML or annotations to configure and map native information ...

Complex multi table query -- Taking supermarket transaction data as an example The previous content is basically based on the query operation of single table, but in practical work, the data is often scattered in multiple tables. At this time, we need to use the knowledge of multi table query. Generally speaking, there are two main types of m ...

Database notes 1 1. Relationship between SQL, DB and DBMS DB: the DataBase exists as a file on the hard disk SQL: structured query language, high-level language, compiled and executed DBMS: DataBase Manager System Mysql, SQLservice, Oracle, DB2, Syba se Relationship: DBMS executes SQL statements and then operates DB data 2. Tables and g ...

How does Python store the crawled data in txt, excel and mysql respectively 1. Page analysis The page I crawled is Tencent sports, and the link is as follows: https://nba.stats.qq.com/player/list.htm **Observe the above figure: * * the left shows 30 NBA teams respectively, and the right shows the details of the corresponding players of ...

Article introduction Many articles on MySQL master-slave replication on the network explain how to implement and some implementation principles, and lack a comprehensive introduction to MySQL master-slave replication. For example, the mode of master-slave replication (semi synchronous mode and asynchronous synchronous mode), the principle ...

1. Introduction to data: Tianchi Taobao User Data 2. Data Import and Cleaning SQL interface tool used this time - SQL workbench 2.1 Importing data create table userbehavior( userID int, itemID int, categoryID int, bahaviortype text, timestamp int ); load data infile "C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/UserBehavior.csv" into ta ...

This article was written because of a recent need: Known field values for a table are irregular comma-separated strings with the following styles: Now split the field into four fields by comma with the following styles: I have not had a ready-made function in Baidu for a long time, so I can only think of my own way. First of all, the simplest ...

nginx installation and operation control Compile and install nginx Install support software The configuration and operation of nginx need the support of pcre, zlib and other software packages Install pcre and zlib You need to mount the Centos image during installation. Clear the yum source [root@centos ~]# yum -y install pcre-devel ...