Mysql database basic operations DML

 MySQL Strong performance , It is one of the most widely used databases at present , With  MySQL For learning the prototype, it is also convenient to master other databases later , Now let's give you Give a comprehensive explanation MySQL8.0 New features , From zero foundation to high-level one-stop learning , Combined with actual cases, we can gain something ！

▼ MySQL8.0 introduction - Advanced learning notes ：（ Summary ）

• The first 1 speak ：SQL Overview and database system introduction
• The first 2 speak ：​​​​​​​MySQL brief introduction 、 Detailed installation steps and use
• The first 3 speak ：MySQL Common graphics management tools ​​​​​​​
• The first 4 speak ：MySQL Basic operation of database -DDL 

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One 、 Basic introduction

DML It refers to the data operation language , The full English name is Data Manipulation Language, Used to update the data records of tables in the database .

keyword ：

• Insert insert
• Delete delete
• to update update

Two 、 Insert data into

Grammar format

insert into  surface  ( Name 1, Name 2, Name 3...) values ( value 1, value 2, value 3...); // Insert some... Into the table 
insert into  surface  values ( value 1, value 2, value 3...);     // Insert all columns... Into the table 

Example

insert into student(sid,name,gender,age,birth,address,score)
                       values(1001,' male ',18,'1996-12-23',' Beijing ',83.5);
insert into student values(1001,' male ',18,'1996-12-23',' Beijing ',83.5);

Data modification

Grammar format

update  Table name  set  Field name = value , Field name = value ...;
update  Table name  set  Field name = value , Field name = value ... where  Conditions ;

Example

--  Change the address of all students to Chongqing  
update student set address = ' Chongqing ’; 

--  speak id by 1004 The address of the student is changed to Beijing  
update student set address = ' Beijing ' where id = 1004 

--  speak id by 1005 The address of the student is changed to Beijing , The grade is revised to 100 
update student set address = ' Guangzhou ',score=100 where id = 1005

Data deletion

Grammar format

delete from  Table name  [where  Conditions ];
truncate table   Table name   perhaps  truncate  Table name 

Example

-- 1. Delete sid by 1004 Student data for 
delete from student where sid  = 1004;
-- 2. Delete all data from the table 
delete from student;
-- 3. Clear table data 
truncate table student;
truncate student;

Be careful ：delete and truncate The principle is different ,delete Only delete content , and truncate Be similar to drop table , It can be understood as deleting the whole table , Then create the table ;

3、 ... and 、 summary

Tableau in , Data sources can be roughly divided into two categories , They are local data sources （ file ） And server data sources （ service ）.

Tableau Sorting is divided into automatic sorting and custom sorting , It can be in the order of data sources 、 Letter 、 Field 、 Manual 、 Sort by nesting rules .