Question

我是SQL的新手，正在学习SQL中的用户定义函数

我有两个表，并且已经将已插入的行添加到这些表中。

--Table1

create table sql_exam(
exa_examid bigint not null primary key,
exa_name varchar(100) not null,
exa_maxmark decimal(5,2) not null,
exa_minmarkreqdforpass decimal(5,2) not null,
exa_examscheduletime datetime not null
)

--Rows inserted into Table1

insert into sql_exam(exa_examid,exa_name,exa_maxmark,exa_minmarkreqdforpass,exa_examscheduletime) values (1,'Maths',100,40,'2012-10-10 10:00')
insert into sql_exam(exa_examid,exa_name,exa_maxmark,exa_minmarkreqdforpass,exa_examscheduletime) values (2,'English',75,35,'2012-10-11 10:00')

--Table2

create table sql_studentmarks(
stm_studentid int not null primary key,
stm_examid bigint foreign key references sql_exam(exa_examid),
stm_mark decimal(5,2)
)

--Rows inserted into Table2
insert into sql_studentmarks(stm_studentid,stm_examid,stm_mark) values (1,1,80)
insert into sql_studentmarks(stm_studentid,stm_examid,stm_mark) values (2,1,90)
insert into sql_studentmarks(stm_studentid,stm_examid,stm_mark) values (3,1,40)
insert into sql_studentmarks(stm_studentid,stm_examid,stm_mark) values (1,2,70)
insert into sql_studentmarks(stm_studentid,stm_examid,stm_mark) values (2,2,60)
insert into sql_studentmarks(stm_studentid,stm_examid,stm_mark) values (3,2,17)

我需要有关创建标量函数的帮助，我需要获取

标量函数，它将返回在“数学”中获得最高分的学生的学生ID
一个表格函数，它将返回学生ID和总分最高的学生所获得的分数。

我只是想学习SQL。我试过 - “

create function fnGetMathsHightest()
returns int
as
begin
declare @st_id int
return @st_id
end



select dbo.fnGetMathsHightest() 
from sql_studentmarks 
where stm_examid=1 
group by stm_studentid 
having stm_mark=max(stm_mark)

第一个。它看起来不太好。

Answer 1

看起来这就是你想要的1。

CREATE FUNCTION ssfnGetStudenytId
(
    -- Add the parameters for the function here
)
RETURNS int
AS
BEGIN

declare @vId as int 
set @vId =  Select stm_studentid  from  sql_studentmarks where stm_mark = (SELECT  MAX( stm_mark )from sql_studentmarks )

RETURN @vId
END

SQL中的用户定义标量函数

1 个答案: