The use of DML in graphical interface tools

/*
Create table format
create table Table name (
         Name 1 Field type 1,
         Name 2 Field type 2,
         Name 3 Field type 3,
        
        ...
         Name n Field type n
) ;
*/
-- A database is a directory , To create a table , Need to enter the current db1 This directory
USE db1; 
SELECT * FROM student;
-- matters needing attention ： Use some fields to insert ： The type should correspond to the order of fields
INSERT INTO student VALUE(252,' Zhang San ',15,' male ');
SELECT * FROM student;
SHOW DATABASES;
DESC student;
-- Delete data delete from Table name ; Delete full table data （ Kill all the records in the table ）
-- Delete data conditionally ：delete from Table name where Conditions
-- Need to delete the student table age by 15 This record of
DELETE FROM student WHERE age=10;

SHOW DATABASES;-- View all databases
SHOW CREATE DATABASE db1;-- View the definition information of the database  
/*
ALTER DATABASE Database name DEFAULT CHARACTER SET Character set ;   Modify the default character set of the database  
DROP DATABASE Database name ;   Delete database                                                                
*/
DESC student;
SELECT * FROM student;

/*
alter Used to modify the basic table , It is to operate the structure of the table , For example, add , Delete , Modification type

update Used to modify the data in the table , Modify the value of a row or column
*/
-- ----------------------------
-- Modify the records in the table
-- Modify with conditions
-- update Table name set Field name = value where Conditional statements ： Modify a single field

-- Bulk changes （ Not recommended ）
UPDATE student SET NAME=" Zhang San ";-- The string value can be in single quotation marks or double quotation marks

-- take id=123 The name of this record is changed to " Li Si "
UPDATE student SET NAME=" Li Si " WHERE id=123;

-- Modify the use of multiple fields according to conditions
-- demand ： take id=252 The name and age of this record are changed to ' Wang Wu ',44
UPDATE student SET NAME=' Wang Wu ',age=44 WHERE id=252;