当前位置:网站首页>CPDA|How Operators Learn Data Analysis (SQL) from Negative Foundations
CPDA|How Operators Learn Data Analysis (SQL) from Negative Foundations
2022-08-05 02:48:00 【hb15302782362】
CPDA|How operators learn data analysis (SQL) from negative foundations
Every newcomer will realize that operation is a job that does not seem to have its own core competitiveness and sense of security.Because every day's work seems to be surrounded by all kinds of trivial matters, and there is only one theme that is eternal, that is - raising needs, constantly raising various needs.
Operators need a hard core skill to enhance their professional value and improve their sense of occupational security, instead of waiting for various scheduling every day: data analysis scheduling, product design scheduling, UI scheduling,Development schedule.
Operations urgently need to use SQL tools to discover more business value from data in time and improve their output.
SQL is probably the most and most important tool used by Internet companies for data analysis. In the entire data analysis process, using SQL to extract data may account for 50%-80% of the entire data analysis process.As for many data analysts, they are nicknamed "Sql Boy/Girl".
The function of the mysql database can be summed up in four words: additions, deletions, changes, and inquiries.
But for us, we can only use the database query function, other permissions are impossible to open to you.
If you think the database is jerky, you can understand it like this:
•SQL?Is an order to access data
• Database?It's like a folder
•Datasheets?It is equivalent to an Excel file in the folder
– the table name is the file name
– each column in the table has a name, which is the column name, and can also be a field
SQL learning can be divided into three parts:
simple query,
associated query,
function reference.
What is a query?
After the database is established, through the most commonly used statement SELECT in the sql command, let us view the data saved in the database, and can conduct certain analysis and induction.
Simple query:
The complete format of the SELECT statement includes 6 clauses:
1. FROM clause: query the table of data and specify the source of the data.
2. WHERE clause: filter conditions for query data.
3. GROUP BY clause: Group the query results matching the WHERE clause.
4. HAVING clause: Condition the grouped results.
5. ORDER BY clause: sort the query results, followed by DESC descending or ASC ascending (default).
6, LIMIT clause: limit the number of rows in the displayed results of the query.
Associated query:
If you want to query multiple tables, you need to use a connection.
Join query is to join two or more tables together to obtain data, which is the most important query in relational database.The connection methods of tables mainly include inner join, outer join and cross join.
1. From specifies the query table name and gives an alias.
2, left join left outer join, all records in the left table and matching records in the right table appear in the query results.
3, inner join inner join, the common records of the left table and the right table appear in the query results.
4, right join right outer join, all records in the right table and matching records in the left table appear in the query results.
5. on Specify the associated conditions.
The result of table join can be clearly displayed by the graph.
Function reference:
The use of functions can improve the efficiency of sql. The most commonly used functions are:
Logical operations: and, or, not;
Numerical operations: round, floor, ceil, rand, exp, sqrt, etc.;
Date functions: from_unixtime, unix_timestamp, year, month, day, hour, minute, second, weekofyear, detediff, date_add, date_sub, etc.;
Conditional functions: if, coalesce, case when, etc.;
String functions: concat, substr, trim, reverse, split, etc.;
Set statistics functions: count, sum, max, min, percentile, etc.
边栏推荐
- Syntax basics (variables, input and output, expressions and sequential statements)
- LeetCode uses the minimum cost to climb the stairs----dp problem
- Multithreading (2)
- How to transfer a single node of Youxuan database to a cluster
- How OpenGL works
- Access Characteristics of Constructor under Inheritance Relationship
- Optimizing the feed flow encountered obstacles, who helped Baidu break the "memory wall"?
- QT: The Magical QVarient
- View handler 踩坑记录
- sql server installation prompts that the username does not exist
猜你喜欢
Regular expression to match a certain string in the middle
DAY22: sqli-labs shooting range clearance wp (Less01~~Less20)
基于左序遍历的数据存储实践
使用二维码传输文件的小工具 - QFileTrans 1.2.0.1
QT MV\MVC structure
Simple description of linked list and simple implementation of code
倒计时 2 天|云原生 Meetup 广州站,等你来!
01 [Foreword Basic Use Core Concepts]
dmp(dump)转储文件
云原生(三十二) | Kubernetes篇之平台存储系统介绍
随机推荐
继承关系下构造方法的访问特点
The 20th day of the special assault version of the sword offer
[In-depth study of 4G/5G/6G topic-51]: URLLC-16-"3GPP URLLC related protocols, specifications, and technical principles in-depth interpretation"-11-High reliability technology-2-Link adaptive enhancem
01 [Foreword Basic Use Core Concepts]
Images using redis cache Linux master-slave synchronization server hard drive full of moved to the new directory which points to be modified
基于左序遍历的数据存储实践
undo问题
ARM Mailbox
C student management system Find student nodes based on student ID
虚拟内存原理与技术
Semi-Decentralized Federated Learning for Cooperative D2D Local Model Aggregation
正则表达式,匹配中间的某一段字符串
Principle and Technology of Virtual Memory
Programmer's Tanabata Romantic Moment
dmp(dump)转储文件
Countdown to 2 days|Cloud native Meetup Guangzhou Station, waiting for you!
UOS系统下ksql应用缺少动态库”libtinfo.so.5“问题
How to transfer a single node of Youxuan database to a cluster
Study Notes-----Left-biased Tree
你要的七夕文案,已为您整理好!