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Editorial Team
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Asked: 2026-05-15T09:18:08+00:00

I am new to SQL so hopefully this has an easy answer. I have

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I am new to SQL so hopefully this has an easy answer.

I have a Students table (studentID, name, statusID) and a StudentsClasses table (studentID, classID). I’ve been asked to create a view from the above tables that returns the following columns:


classID: (group-by)

count of students in each class AS Students

count of students where statusID = 1 As Actives

count of students where statusID = 2 As Inactives

I can easily group-by the classID colunm and count the number of students, but i dont think the count function can be told to count only certain rows. As soon as I add where or Having clauses I lose records that I need to be counted in other columns. Do I need to write a couple of different queries and then join the results of each?

Thanks for any help you can provide!

-David

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1 Answer

  1. Editorial Team

    This is ANSI SQL (should work as long as your SQL implementation is ANSI compatible):

    SELECT 
 classID,
 COUNT(*) AS "Students",
 SUM(CASE statusID WHEN 1 THEN 1 ELSE 0 END) AS "Actives",
 SUM(CASE statusID WHEN 2 THEN 1 ELSE 0 END) AS "Inactives",
FROM StudentsClasses class
INNER JOIN Students stud ON class.studentID = stud.studentID
GROUP BY classID
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