SQL knowledge points 001-SQL query basic structure

SQL learning is on the way, a little bit every day, SQL will not be difficult

Tutorial content

Generally, each SQL starts with a predicate (Verb), which mainly describes the action to be produced by this statement, such as SELECT or UPDATE keywords; the predicate is followed by one or more clauses (Clause), which mainly gives the predicate or The content information to be executed by the action.

The basic SQL query statement structure usually has SELECT and FROM keywords. The specific structure and keywords are as follows:

SELECT 子句
[INTO 子句]
FROM 子句
[WHERE 子句]
[GROUP BY 子句]
[HAVING 子句]
[ORDER BY 子句]

The above structure is the basic query structure of SQL , and the conditions in [] are conditions that can be added when needed. SELECT and FROM must have

Practice questions

Leetcode practice questions

CODE:

select 
    name,
    population,
    area
from 
    World
where
    area > 3000000
    or
    population >25000000

result: