Basic SQL general syntax and classification

General grammar

1.SQL Sentences can be chilly or multiline , It ends with a semicolon .

2.SQL Statements can use spaces or indents to enhance the readability of statements .

3.MySQL Database SQL Statement is case insensitive , It is recommended to use uppercase .

4. notes ：

        1） Single-line comments ： -- The comment perhaps # The comment （mysql specific ）

        2） Multiline comment ： /* The comment */

classification

DDL	data definition language	Data definition language , Used to define database objects （ database , surface , Field ）
DML	data manipulation language	Data operation language , It is used to add, delete and modify the data in the database table
DQL	data query language	Data query language , Used to query the bid winning records in the database
DCL	data control language	Data control language , Used to create database users 、 Control access to the database

Here is a summary , Now let's start the detailed explanation of each class .