database related issue

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Hi,

I want to fetch data from three table of database in which i am getting exception,query which i am using is

SQL

select StudentInfoId, RegistrationNo,FirstName,MiddleName,LastName,FathersName,MothersName,DateOfBirth,CurrentClassNo,SectionNo,RollNO,Status,MobileNo,CAddress1,CCity,CZipCode,PAddress2,PCity,PZipCode,FathersOccupation,HouseAllocated,Medium.MediumName,SubjectName,Height,Weight,IdMarks1 from StudentInfo,Medium,Subjects where RegistrationNo='1' and Medium.MediumId=StudentInfo.Medium and StudentInfo.Subjects=Subjects.SubjectId

The Exception is "Conversion failed when converting the varchar value |2|3| to data type smallint". where |2|3| is the data in the field of StudentInfo.Subjects.
Here StudentInfo.Subjects is of type varchar and Subjects.SubjectId is of type smallint.

Pls suggest me a way to do same.

Thanks
Abhishek

Posted 13-Jun-11 1:46am

abhiamity86

Updated 13-Jun-11 1:55am

CPallini

v3

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CPallini · Answer 1 · 2011-06-13T02:01:00

Solution 1

The query failure shows a flaw in your data definition: the field 'Subjects' is actually a set (of smallints) and should find place into a separate table. For instance, assuming StudentInfoId is a primary key, you should have

StudententInfoId	Subject
100	2
100	3

to represent the subjects 2,3 for the student having id=100.

Posted 13-Jun-11 2:01am

CPallini

Updated 13-Jun-11 2:02am

v4

Comments

abhiamity86 16-Jun-11 2:46am

Thank for reply,
Exactely but how to do it pls suggest me.

CPallini 16-Jun-11 3:03am

I already suggested you what to do: move the {StudentInfoId, Subject} link to another table (we call it normalization). Please read a database tutorial if this technique doesn't look clear to you.

parmar_punit · Answer 2 · 2011-06-13T02:19:00

Solution 2

better to use join query.....
for more details on join query see the below link
Link1[^]
Link2[^]

Posted 13-Jun-11 2:19am

parmar_punit