首页 > 其他 > 详细

模糊查询于聚合函数

时间:2018-12-18 12:51:00      阅读:123      评论:0      收藏:0      [点我收藏+]

通配符:

  _  单个字符  %任意字符  []范围内的字符  [^]范围外的字符

SELECT * FROM Student
UPDATE Student SET StudentName=‘王波‘ WHERE StudentNo=‘Y21003011‘


--模糊查询:查询学生表中姓’冯‘的学生记录
SELECT * FROM Student WHERE StudentName LIKE ‘王_‘
SELECT * FROM Result WHERE SubjectId LIKE ‘[1-9]‘
SELECT * FROM Result WHERE SubjectId LIKE ‘[^1-3]‘
--查询空的数据行
SELECT * FROM Student WHERE Email=‘‘

--查询区间内数据:BETWEEN AND
SELECT * FROM Result WHERE SubjectId BETWEEN 1 AND 10

--查询与列所匹配值相同的数据:IN
SELECT * FROM Student WHERE Address IN (‘新疆乌鲁木齐‘,‘北京市海淀区五道口北大青鸟IT职业技术学院‘,‘黑龙江哈尔滨‘)

--聚合函数
--1.求和:SUM()
SELECT SUM(StudentResult) AS ‘总成绩‘,Result.SubjectId FROM Result WHERE SubjectId=3

--2.平均值
SELECT AVG(StudentResult) AS ‘平均成绩‘ FROM Result

--3.最大值,最小值
SELECT MAX(StudentResult) AS ‘最高成绩‘ FROM Result
SELECT MIN(StudentResult) AS ‘最低成绩‘ FROM Result

--4.统计记录数:COUNT(*)和COUNT(1)的区别
SELECT COUNT(StudentNo) AS ‘记录数‘ FROM Result

模糊查询于聚合函数

原文:https://www.cnblogs.com/whtt/p/10136397.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!