DQL-分页和排序-2022-11-30

分页和排序

--排序 升序 ASC  降序 DESC 

-- 语法 ORDER BY  

 SELECT s.`studentno`,studentname,`subjectno`,`studentresult`

FROM student AS s
LEFT JOIN result AS r
ON s.studentno = r.studentno
ORDER BY studentresult DESC

SELECT s.`studentno`,studentname,`subjectno`,`studentresult`
FROM student AS s
LEFT JOIN result AS r
ON s.studentno = r.studentno
ORDER BY studentresult ASC

分页

缓解数据库的压力，也有使用瀑布流的，不使用分页，百度的图片就是这个逻辑

每页只显示5条数据

语法 limit  查询起始下标 页面大小pagesize

SELECT s.`studentno`,studentname,`subjectno`,`studentresult`
FROM student AS s
LEFT JOIN result AS r
ON s.studentno = r.studentno
ORDER BY studentresult ASC
LIMIT 0,5