【中字】SQL进阶教程 | 史上最易懂SQL教程！10小时零基础成长SQL大师！

P2

relational

nosql

SQL: structured query language

P3: download on MAC： Just follow the instructions

after downloading the sql server, a graphic tool is needed to connect to the server and manage the database

一头雾水但是跟着做完了，下好了希望学的时候能有点头绪。

step1:first 4 sessions:

retrieve, insert, update and delete data

step 2:

summarizing data

writing complex queries

built-in functions

views

stored procedures

step 3:

triggers

events

transactions

concurrency

step 4:

designing databases

indexing for high performance

securing database: create user account/ limit the access

use sql_store

所有这些字句都可以选，但是不能改变顺序

from-》where-〉order by

给行赋名：

AS

how to create column name with space:

唯一值返回？

>

>=

<

<=

=

!= 不等号

<> 不等号

优先级 AND > OR

用括号来改变优先级

NOT

每日打卡+现实打工辅助实践，看看多久能学完：

2023/02/22: 第一章P1-P6 第二章P7-P9

2023/02/23: