MySQL additions and deletions to change the common syntax

Classification of SQL statements by function (definition, manipulation, control, query)
DDL data Definition language, defining tables, libraries, views
DML Add, modify, and delete operations on data table records
DCL authorization, transaction control, conditional judgment
DQL (not a category given by the organization) Data Sheet record query
That is, the creation, deletion, modification of the database, Gen, delete, modify the table, etc. (belongs to the DDL statement)
Adding and deleting Data insert Delete update (belongs to DML statement) (truncate delete) belongs to DDL
Query for data table records (belongs to DQL statement)
1. Creating a database creates a separate database for each software system:
Syntax: CREATE database name; (CREATE database with database server default character set)
Complex syntax Create database name character Set character set collate comparison rules;
For example, create a database called MYDB1. Create Database mydb1;
Create a MYDB2 database that uses the UTF8 character set. Create database mydb2 character set UTF8;
Create a MYDB3 database that uses the UTF8 character set and with the proofing rules. Create database mydb3 character set UTF8 collate utf8_bin;
Add: Each time a database is created, a folder is generated in the data store directory, and Db.opt holds the default character set and proofing rules for each folder
2. Querying the Database
show databases; -----View all databases
Show create database name; ------Viewing Data encoding sets
3. Delete Database
Syntax: drop database name;
For example: View all databases in the current database server show databases;
View the definition information for the MYDB2 database created earlier show create Database mydb2;
Delete the MYDB1 database that you created earlier, drop DB mydb1;
4. Modify the database encoding set
Syntax: ALTER DATABASE name character Set character set collate comparison rules;
For example: Modify the MYDB2 character set to GBK; ALTER DATABASE MYDB2 character set GBK;
Toggle Current Usage Database: Use database name
View currently in use database: select databases ();
Note: All database-related operation statements belong to the DDL statement