Regarding sql query requirement

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HI all,

I have three tables
1. Organisation table
2. Class table
2. Student Table

Columns in organisation table are

Id, orgname, orgAddress

Columns in class table are

Id, Orgid,Classname
Note(Id column of orgtable is fk for Orgid in class table)

Columns in student table are

Id,ClassId,StudentName,Address,PhoneNo
Note(Id column of class table is fk for ClassId in student table)

So my requirement is i need complete organisation details along with student count for each organisation

Output:
Slno, orgname, orgAddress, student count
1 pvrInstitute Banglore 30
2 nskInstitute naagpur 50

What I have tried:

HI all,

I have three tables
1. Organisation table
2. Class table
2. Student Table

Columns in organisation table are

Id, orgname, orgAddress

Columns in class table are

Id, Orgid,Classname
Note(Id column of orgtable is fk for Orgid in class table)

Columns in student table are

Id,ClassId,StudentName,Address,PhoneNo
Note(Id column of class table is fk for ClassId in student table)

So my requirement is i need complete organisation details along with student count for each organisation

Output:
Slno, orgname, orgAddress, student count
1 pvrInstitute Banglore 30
2 nskInstitute naagpur 50

Posted 21-Feb-16 21:41pm

kalyan10qwerty

Updated 22-Feb-16 13:13pm

Kuthuparakkal

v2

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2 solutions

Solution 1

Use a JOIN: SQL Joins[^]
This is your homework, so I'll not give you the code. Just read the article, and see how it works - it's not complex, so follow the example with yoru DB and you should be fine.

Posted 21-Feb-16 22:07pm

OriginalGriff

Comments

kalyan10qwerty 22-Feb-16 4:22am

Hi OriginalGriff

I have tried half query
select count(*) from Students s,Classes c,Organisations o where s.ClassId=c.Id and c.OrganisationId=o.Id

now i need orgname which is in orgtable along with the above query so please help me

OriginalGriff 22-Feb-16 4:31am

Yes - that's why you want a JOIN.
Follow the link - it's not difficult to do!

kalyan10qwerty 22-Feb-16 4:33am

yes your right. but i am unable to write complete query even though after referring to the information provided by you. so give me the solution

OriginalGriff 22-Feb-16 4:50am

What did you try after reading it?

kalyan10qwerty 22-Feb-16 4:56am

select o.organisationcode, o.organisationname, ( select count(*) from Students s,Classes c,Organisations o where s.ClassId=c.Id and c.OrganisationId=o.Id ) as StudentCount from Organisations o,Students s,Classes c
where s.ClassId=c.Id and c.OrganisationId=o.Id

In studentCount it is retrieving all organisation students count in-stud of that particular org student count :(. Some where i am missing the condition. Unable to figure it out. So help me

OriginalGriff 22-Feb-16 5:09am

So...you didn't follow the link, you didn't read it, and you didn't try a JOIN then.
Is there any point in my trying to help you if you ignore everything I suggest?

kalyan10qwerty 22-Feb-16 5:11am

select count(*) from Students s, Organisations o, Classes c
where s.ClassId=c.Id and c.OrganisationId=o.Id and o.OrganisationCode='204050'

above is the query for which i got student count as i specified the particular organisation code.
I have around 800 org so please give me the solution

OriginalGriff 22-Feb-16 5:16am

Read the link: this is your homework, so you need to learn this stuff. Your tutor wants your solution, not mine!
Seriously, this isn't complicated...

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kalyan10qwerty · Accepted Answer · 2016-02-22T13:13:00

Solution 3

I got the solution

C#

SELECT o.Id, o.OrganisationCode, o.OrganisationName, count(*) As StudentCount
FROM Students S
INNER JOIN Classes C on s.ClassId = C.Id 
INNER JOIN Organisations O on c.OrganisationId = o.Id
GROUP BY o.Id, o.OrganisationCode, o.OrganisationName

Posted 22-Feb-16 13:13pm

kalyan10qwerty