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Hello, everyone. I'm Mr. Tony, who only talks about technology and doesn't cut his hair. Today, we introduce an application CASE of CASE conditional expression, using the example table Click here to download. If the company is about to celebrate its 20th anniversary, it plans to distribute an anniversary gift to all employees. The rules for ...

Welcome to the MySQL technical articles shared by the great SQL community. If you have any questions or want to learn, you can leave a message in the comment area below. After seeing it, you will answer itproblemRun the following Python code, but you can't always update the data:import pymysql conn=pymysql.connect( host = '127.0.0.1', user = 'y ...

preface Interviewer: let's say, how do you query 10 million data? Brother B: direct paging query, using limit paging. Interviewer: have you practiced it? Brother B: there must be Here's a song "cool" Maybe some people have never met a table with tens of millions of data, and they don't know what will happen when querying tens o ...

1, Annotation development 1.1 comparison between annotations and xml xml: as a configuration file Advantages: it can extract content (decoupling), clear configuration, convenient positioning and easy to findDisadvantages: complicated configuration Note: xml development can be replaced Advantages: fast development speed and no cumbersom ...

JavaScript JavaScript overview summary Is a scripting language that is parsed and executed directly by the browser Development history In 1995, Netscape developed a client script language: LiveScript. Later, experts from SUN company were invited to modify LiveScript and name it JavaScriptIn 1996, Microsoft copied JavaScript and developed JS ...

The second day Preparing data CREATE TABLE student ( id int, -- number name varchar(20), -- Full name age int, -- Age sex varchar(5), -- Gender address varchar(100), -- address math int, -- Mathematics english int -- English ); INSERT INTO student(id,NAME,age,sex,address,math,english) VALUES (1,'Jack Ma',55,'ma ...

        There are six tables in the online library with duplicate data, two of which are relatively large, one 960000 + and one 300000 +. Because the same problem has been handled before, we directly brought the last Python de duplication script. The script is very simple, that is, connect to the database, find out the dupli ...

Several ways to write SQL circular statements From: https://www.cnblogs.com/guorongtao/p/11939751.html Several ways to write SQL circular statements 1. Normal loop statement 1 2 3 4 5 6 7 8 9 10 11 12 13 14 declare @orderNum varchar(255) create table #ttableName(id int identity(1,1),Orders varchar(255)) declare @n int,@rows int inser ...

1, Short answer 1. Briefly describe the MySQL version used by your company, and specify the specific minor version and GA time? 5.6.38 5.7.20 2017-9-13 2. Please introduce the type of database you are familiar with and the representative product name? NoSQL:Redis Mongodb memcache RDBMS:Oracle MySQL MSSQL PG 3. Please briefly describ ...

Addition, deletion and modification of data processing 1, Insert data 1.1 practical problems Solution: use the INSERT statement to INSERT data into the table. 1.2 mode 1: add VALUES Using this syntax, only one piece of data can be inserted into the table at a time. Case 1: insert data in the default order for all fields of the table ...