AliangYeah的博客

一、Datetime数据的简单处理1. YEAR(), MONTH(), DAY()2.DATEPART(),DATENAME()3.DATEADD(),DATEDIFF()二、Datetime数据的格式处理1. CAST(), CONVERT()We can use theCAST()function to translate data between various data types, including between date/time types...

select > distinct > from > join > on > where > group by > having > order by > limit

一、常用函数1. 聚合函数SUM(), 求和AVG(), 平均MAX(), 最大值MIN(), 最小值COUNT(), 计数2. 文本连接 - 将first_name, " ", last_name合并成一个字符串SQL - first_name|| " " || last_nameMySQL - CONCAT(first_name, " ", last_name)3. 文本截取LEFT(x, n)返回字符串 x 中的最前n个字符(从最左边开始数)RIGHT.