mysql 查询语句构造数据项序号

一 、自定义变量

SELECT (@n:=@n+1) AS num FROM article;

二、使用ROW_NUMBER() 函数(用时较短)

SELECT ROW_NUMBER() over(order by title DESC) AS n FROM article;
SELECT ROW_NUMBER() over() AS n FROM article;

三、两个表构造行号进行连接查询

SELECT t1.title, t2.slug FROM 
 (SELECT ROW_NUMBER() over() AS n, title FROM article) t1
 LEFT JOIN (
	SELECT ROW_NUMBER() over() AS n, slug FROM article_category
 )
 t2 ON t1.n=t2.n