php代码中,用SQL语句查询查询数据库里面的信息,并显示出来

php代码中,用SQL语句查询查询数据库里面的信息,并显示出来,第1张

php代码中,用SQL语句查询查询数据库里面的信息,并显示出来

$question

$sql=

"select

from

tableName

where

question='$question'

";

//tableName

是你数据库的名字

//

question

是你数据库的字段名字

//

$question

是你问题的答案

select from table

where rownum<(select count()+1 from table)

minus

select from table

where rownum<(select count() from table)

也可以简化为

select from table

minus

select from table

where rownum<(select count() from table)

效果是一样的

切记rownum是伪列 只能用<

dl_会飞的青蛙的答案是错误的,他给出的是降序排列后的第一条,仅在排序过的时候是正确的。如果这个表是不排序的呢?他的答案就是错的

顺便给你求第X行的通用SQL语句

select from table where rownum<X+1

minus

select from table where rownum<X

就是返回到数据库,这个看你用什么方式了。如果你用sql语句,那么就是建立数据库连接,然后发送插入的sql语句。执行。如果是adonet里面通过datatable添加的,那么需要调用dataadpterupdate方法。网上有的,搜索下。

数据库常用sql语句有哪些

SQL语句有哪些?SQL语句无论是种类还是数量都是繁多的,很多语句也是经常要用到的,下文我为大家分享的就是SQL的常用语句,仅供参考!

50个常用的sql语句

Student(S#,Sname,Sage,Ssex) 学生表

Course(C#,Cname,T#) 课程

SC(S#,C#,score) 成绩

Teacher(T#,Tname) 教师表

问题:

1、查询“001”课程比“002”课程成绩高的所有学生的学号

select aS# from (select s#,score from SC where C#='001') a,(select s#,score

from SC where C#='002') b

where ascore>bscore and as#=bs#;

2、查询平均成绩大于60分的同学的学号和平均成绩;

select S#,avg(score)

from sc

group by S# having avg(score) >60;

3、查询所有同学的学号、姓名、选课数、总成绩;

select StudentS#,StudentSname,count(SCC#),sum(score)

from Student left Outer join SC on StudentS#=SCS#

group by StudentS#,Sname

4、查询姓“李”的老师的个数;

select count(distinct(Tname))

from Teacher

where Tname like '李%';

5、查询没学过“叶平”老师课的同学的学号、姓名;

select StudentS#,StudentSname

from Student

where S# not in (select distinct( SCS#) from SC,Course,Teacher where SCC#=CourseC# and TeacherT#=CourseT# and TeacherTname='叶平');

6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名;

select StudentS#,StudentSname from Student,SC where StudentS#=SCS# and SCC#='001'and exists( Select from SC as SC_2 where SC_2S#=SCS# and SC_2C#='002');

7、查询学过“叶平”老师所教的所有课的同学的学号、姓名;

select S#,Sname

from Student

where S# in (select S# from SC ,Course ,Teacher where SCC#=CourseC# and TeacherT#=CourseT# and TeacherTname='叶平' group by S# having count(SCC#)=(select count(C#) from Course,Teacher where TeacherT#=CourseT# and Tname='叶平'));

8、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名;

Select S#,Sname from (select StudentS#,StudentSname,score ,(select score from SC SC_2 where SC_2S#=StudentS# and SC_2C#='002') score2

from Student,SC where StudentS#=SCS# and C#='001') S_2 where score2 <score;

9、查询所有课程成绩小于60分的同学的学号、姓名;

select S#,Sname

from Student

where S# not in (select StudentS# from Student,SC where SS#=SCS# and score>60);

10、查询没有学全所有课的同学的学号、姓名;

select StudentS#,StudentSname

from Student,SC

where StudentS#=SCS# group by StudentS#,StudentSname having count(C#) <(select count(C#) from Course);

11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名;

select S#,Sname from Student,SC where StudentS#=SCS# and C# in select C# from SC where S#='1001';

12、查询至少学过学号为“001”同学所有一门课的其他同学学号和姓名;

select distinct SCS#,Sname

from Student,SC

where StudentS#=SCS# and C# in (select C# from SC where S#='001');

13、把“SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩;

update SC set score=(select avg(SC_2score)

from SC SC_2

where SC_2C#=SCC# ) from Course,Teacher where CourseC#=SCC# and CourseT#=TeacherT# and TeacherTname='叶平');

14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名;

select S# from SC where C# in (select C# from SC where S#='1002')

group by S# having count()=(select count() from SC where S#='1002');

15、删除学习“叶平”老师课的SC表记录;

Delect SC

from course ,Teacher

where CourseC#=SCC# and CourseT#= TeacherT# and Tname='叶平';

16、向SC表中插入一些记录,这些记录要求符合以下条件:没有上过编号“003”课程的同学学号、2、

号课的平均成绩;

Insert SC select S#,'002',(Select avg(score)

from SC where C#='002') from Student where S# not in (Select S# from SC where C#='002');

17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩,按如下形式显示: 学生ID,,数据库,企业管理,英语,有效课程数,有效平均分

SELECT S# as 学生ID

,(SELECT score FROM SC WHERE SCS#=tS# AND C#='004') AS 数据库

,(SELECT score FROM SC WHERE SCS#=tS# AND C#='001') AS 企业管理

,(SELECT score FROM SC WHERE SCS#=tS# AND C#='006') AS 英语

,COUNT() AS 有效课程数, AVG(tscore) AS 平均成绩

FROM SC AS t

GROUP BY S#

ORDER BY avg(tscore)

18、查询各科成绩最高和最低的分:以如下形式显示:课程ID,最高分,最低分

SELECT LC# As 课程ID,Lscore AS 最高分,Rscore AS 最低分

FROM SC L ,SC AS R

WHERE LC# = RC# and

Lscore = (SELECT MAX(ILscore)

FROM SC AS IL,Student AS IM

WHERE LC# = ILC# and IMS#=ILS#

GROUP BY ILC#)

AND

RScore = (SELECT MIN(IRscore)

FROM SC AS IR

WHERE RC# = IRC#

GROUP BY IRC#

);

19、按各科平均成绩从低到高和及格率的百分数从高到低顺序

SELECT tC# AS 课程号,max(courseCname)AS 课程名,isnull(AVG(score),0) AS 平均成绩

,100 SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT() AS 及格百分数

FROM SC T,Course

where tC#=courseC#

GROUP BY tC#

ORDER BY 100 SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT() DESC

20、查询如下课程平均成绩和及格率的百分数(用"1行"显示): 企业管理(001),马克思(002),OO&UML (003),数据库(004)

SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分

,100 SUM(CASE WHEN C# = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数

,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分

,100 SUM(CASE WHEN C# = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数

,SUM(CASE WHEN C# = '003' THEN score ELSE 0 END)/SUM(CASE C# WHEN '003' THEN 1 ELSE 0 END) AS UML平均分

,100 SUM(CASE WHEN C# = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '003' THEN 1 ELSE 0 END) AS UML及格百分数

,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分

,100 SUM(CASE WHEN C# = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数

FROM SC

21、查询不同老师所教不同课程平均分从高到低显示

SELECT max(ZT#) AS 教师ID,MAX(ZTname) AS 教师姓名,CC# AS 课程ID,MAX(CCname) AS 课程名称,AVG(Score) AS 平均成绩

FROM SC AS T,Course AS C ,Teacher AS Z

where TC#=CC# and CT#=ZT#

GROUP BY CC#

ORDER BY AVG(Score) DESC

22、查询如下课程成绩第 3 名到第 6 名的学生成绩单:企业管理(001),马克思(002),UML (003),数据库(004)

[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩

SELECT DISTINCT top 3

SCS# As 学生学号,

StudentSname AS 学生姓名 ,

T1score AS 企业管理,

T2score AS 马克思,

T3score AS UML,

T4score AS 数据库,

ISNULL(T1score,0) + ISNULL(T2score,0) + ISNULL(T3score,0) + ISNULL(T4score,0) as 总分

FROM Student,SC LEFT JOIN SC AS T1

ON SCS# = T1S# AND T1C# = '001'

LEFT JOIN SC AS T2

ON SCS# = T2S# AND T2C# = '002'

LEFT JOIN SC AS T3

ON SCS# = T3S# AND T3C# = '003'

LEFT JOIN SC AS T4

ON SCS# = T4S# AND T4C# = '004'

WHERE studentS#=SCS# and

ISNULL(T1score,0) + ISNULL(T2score,0) + ISNULL(T3score,0) + ISNULL(T4score,0)

NOT IN

(SELECT

DISTINCT

TOP 15 WITH TIES

ISNULL(T1score,0) + ISNULL(T2score,0) + ISNULL(T3score,0) + ISNULL(T4score,0)

FROM sc

LEFT JOIN sc AS T1

ON scS# = T1S# AND T1C# = 'k1'

LEFT JOIN sc AS T2

ON scS# = T2S# AND T2C# = 'k2'

LEFT JOIN sc AS T3

ON scS# = T3S# AND T3C# = 'k3'

LEFT JOIN sc AS T4

ON scS# = T4S# AND T4C# = 'k4'

ORDER BY ISNULL(T1score,0) + ISNULL(T2score,0) + ISNULL(T3score,0) + ISNULL(T4score,0) DESC);

23、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60]

SELECT SCC# as 课程ID, Cname as 课程名称

,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]

,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70]

,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60]

,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS [60 -]

FROM SC,Course

where SCC#=CourseC#

GROUP BY SCC#,Cname;

24、查询学生平均成绩及其名次

SELECT 1+(SELECT COUNT( distinct 平均成绩)

FROM (SELECT S#,AVG(score) AS 平均成绩

FROM SC

GROUP BY S#

) AS T1

WHERE 平均成绩 > T2平均成绩) as 名次,

S# as 学生学号,平均成绩

FROM (SELECT S#,AVG(score) 平均成绩

FROM SC

GROUP BY S#

) AS T2

ORDER BY 平均成绩 desc;

25、查询各科成绩前三名的记录:(不考虑成绩并列情况)

SELECT t1S# as 学生ID,t1C# as 课程ID,Score as 分数

FROM SC t1

WHERE score IN (SELECT TOP 3 score

FROM SC

WHERE t1C#= C#

ORDER BY score DESC

)

ORDER BY t1C#;

26、查询每门课程被选修的学生数

select c#,count(S#) from sc group by C#;

27、查询出只选修了一门课程的全部学生的学号和姓名

select SCS#,StudentSname,count(C#) AS 选课数

from SC ,Student

where SCS#=StudentS# group by SCS# ,StudentSname having count(C#)=1;

28、查询男生、女生人数

Select count(Ssex) as 男生人数 from Student group by Ssex having Ssex='男';

Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex='女';

29、查询姓“张”的学生名单

SELECT Sname FROM Student WHERE Sname like '张%';

30、查询同名同性学生名单,并统计同名人数

select Sname,count() from Student group by Sname having count()>1;;

31、1981年出生的学生名单(注:Student表中Sage列的类型是datetime)

select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age

from student

where CONVERT(char(11),DATEPART(year,Sage))='1981';

32、查询每门课程的平均成绩,结果按平均成绩升序排列,平均成绩相同时,按课程号降序排列

Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;

33、查询平均成绩大于85的所有学生的学号、姓名和平均成绩

select Sname,SCS# ,avg(score)

from Student,SC

where StudentS#=SCS# group by SCS#,Sname having    avg(score)>85;

34、查询课程名称为“数据库”,且分数低于60的学生姓名和分数

Select Sname,isnull(score,0)

from Student,SC,Course

where SCS#=StudentS# and SCC#=CourseC# and CourseCname='数据库'and score <60;

35、查询所有学生的选课情况;

SELECT SCS#,SCC#,Sname,Cname

FROM SC,Student,Course

where SCS#=StudentS# and SCC#=CourseC# ;

36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数;

SELECT distinct studentS#,studentSname,SCC#,SCscore

FROM student,Sc

WHERE SCscore>=70 AND SCS#=studentS#;

37、查询不及格的课程,并按课程号从大到小排列

select c# from sc where scor e <60 order by C# ;

38、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名;

select SCS#,StudentSname from SC,Student where SCS#=StudentS# and Score>80 and C#='003';

39、求选了课程的学生人数

select count() from sc;

40、查询选修“叶平”老师所授课程的学生中,成绩最高的学生姓名及其成绩

select StudentSname,score

from Student,SC,Course C,Teacher

where StudentS#=SCS# and SCC#=CC# and CT#=TeacherT# and TeacherTname='叶平' and SCscore=(select max(score)from SC where C#=CC# );

41、查询各个课程及相应的选修人数

select count() from sc group by C#;

42、查询不同课程成绩相同的学生的学号、课程号、学生成绩

select distinct AS#,Bscore from SC A ,SC B where AScore=BScore and AC# <>BC# ;

43、查询每门功成绩最好的前两名

SELECT t1S# as 学生ID,t1C# as 课程ID,Score as 分数

FROM SC t1

WHERE score IN (SELECT TOP 2 score

FROM SC

WHERE t1C#= C#

ORDER BY score DESC

)

ORDER BY t1C#;

44、统计每门课程的学生选修人数(超过10人的课程才统计)。要求输出课程号和选修人数,查询结果按人数降序排列,查询结果按人数降序排列,若人数相同,按课程号升序排列

select C# as 课程号,count() as 人数

from sc

group by C#

order by count() desc,c#

45、检索至少选修两门课程的学生学号

select S#

from sc

group by s#

having count() > = 2

46、查询全部学生都选修的课程的课程号和课程名

select C#,Cname

from Course

where C# in (select c# from sc group by c#)

47、查询没学过“叶平”老师讲授的任一门课程的学生姓名

select Sname from Student where S# not in (select S# from Course,Teacher,SC where CourseT#=TeacherT# and SCC#=courseC# and Tname='叶平');

48、查询两门以上不及格课程的同学的学号及其平均成绩

select S#,avg(isnull(score,0)) from SC where S# in (select S# from SC where score <60 group by S# having count()>2)group by S#;

49、检索“004”课程分数小于60,按分数降序排列的同学学号

select S# from SC where C#='004'and score <60 order by score desc;

50、删除“002”同学的“001”课程的成绩

delete from Sc where S#='001'and C#='001';

;

你好,请问你是jsp,php,asp呢。

一般在网页中显示数据库所查找到的信息,基本是一样的。

在网页中需要显示数据库信息的地方,写上语句,我以jsp为例子

一般网页开发都遵循MVC模式。至于什么是MVC模式,就不赘述了。

1一般对应数据库的那么表,我们会在webproject中创建一个javabean,也就是Namejava。

2里面的成员变量,就跟数据库的列名一样的,一般设置是private的,然后通过getter,setter方法来给予访问。

3另外数据库的链接 *** 作,最好有个java类创建数据库的连接及释放

4创建一个对name‘表的 *** 作的Java类。这里就称为。

主要是从数据库中查找所有的用户,返回当然是一个List集合

接下来,可以在网页中显示了

Listlist=();//具体方法不再赘述

for(inti=0;i

Namename=(Name)listget(i);

%>

//假设这里显示四个用户名

用户名:

%>

简单点的父子结构

select ccategory_id, cname, cparent_id from category c where cparent_id = 0

union

select c1category_id, concat(c1name,'>','c2name') name, c2parent_id from category c1, category c2 

where c1parent_id>0

and c1category_id = c2parent_id

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