SQL training camp -- Task02: SQL basic query and sorting

This note is the learning content of Alibaba cloud Tianchi Longzhu plan SQL training camp. The link is: https://tianchi.aliyun.com/specials/promotion/aicampsql preface This note is the learning content of Alibaba cloud Tianchi Longzhu plan SQL training camp. The link is: https://tianchi.aliyun.com/specials/promotion/aicampsql 1. Part ...

Posted on Wed, 24 Nov 2021 12:47:59 -0500 by enchance

MySQL Learning Notes (12) - SQL Trigger:

12. SQL triggers MySQL triggers, like stored procedures, are a program embedded in MySQL. Triggers are events that trigger an action, including INSERT, UPDATAE, and DELETE statements. If triggers are defined, they will be triggered when the database executes these statements to perform the appropriate actions. A trigger is a named database obj ...

Posted on Wed, 24 Nov 2021 12:26:07 -0500 by Frame

Analyze the working principle of MyBatis from the perspective of source code

1, MyBatis complete example Here, I'll use an entry-level example to demonstrate how MyBatis works. Note: the principles and source code in the later chapters of this article will also be explained based on this example. Full sample source address 1.1. Database preparation In this example, CRUD operation is required for a user table. The da ...

Posted on Wed, 24 Nov 2021 11:12:47 -0500 by jinwu

Various functions in SQL

Learning focus According to the purpose, functions can be roughly divided into arithmetic functions, string functions, date functions, conversion functions and aggregate functions. There are many kinds of functions. You don't need to remember them all. Just remember the representative functions. Others can be queried when you use them. ...

Posted on Wed, 24 Nov 2021 09:25:14 -0500 by netdog

Python summary (primary data structure list and array)

1. Lists and tuples          The list is dynamic and its length is not fixed. You can add, delete or change elements (mutable) at will.          Tuples are static, with fixed length and size, and cannot be added, deleted or immutable.          tup = (1, 2, 3, 4) ...

Posted on Mon, 22 Nov 2021 12:29:46 -0500 by iamtheironman

ch2 data management

preface Database management is very important. This paper is based on mysql8.0 text Account Management Create a new account create user 'root'@'localhost' identified by '123456'; create user 'root'@'%' identified by '123456'; "localhost" means that the user can only log in locally, and the remote login is "%" Set a ...

Posted on Mon, 22 Nov 2021 10:51:25 -0500 by synical21

Python summary (primary data structure dictionary and collection)

Dictionary and collection Basics What is a dictionary and what is a collection? A dictionary is a set of elements composed of key and value pairing. In Python 3.7 + dictionary, it is determined to be ordered (Note: in 3.6, dictionary order is an implementation detail, which is officially called a language feature in 3.7, so it cannot be 100% g ...

Posted on Mon, 22 Nov 2021 04:30:41 -0500 by horstuff

Database Experiment 6

Experiment 6: advanced query of data table Experimental content Note: all the following tables are based on XSKC mode with Experiment 5 Based on database, please use T-SQL statement to perform the following operations: Query the name and student number of the student whose second word in the name is "Xiang", as well as the elective ...

Posted on Sat, 20 Nov 2021 19:11:00 -0500 by hbuchel

Introduction to database system (Fifth Edition) Chapter 3 relational database standard language SQL

3.1 SQL overview Structured Query Language mysql installation install 3.2 student course database 3.3 data definition Enter mysql mysql; or mysql -uroot -p Create database CREATE DATABASE cyp; View created databases In the early days, databases and schema s were essentially the same And sql keywords are not case sensitive, ...

Posted on Sat, 20 Nov 2021 16:13:59 -0500 by markbm

Day455. Basic SELECT statement & operator mysql

Basic SELECT statement 1, SQL overview 1. SQL background In 1974, IBM researchers published a paper "sequence: a structured English query language", which unveiled database technology. Up to now, this structured query language has not changed much. Compared with other languages, the half-life of SQL can be said to be very long. S ...

Posted on Sat, 20 Nov 2021 09:34:12 -0500 by Arrow