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MS SQL JOIN Syntax
I need help with an SQL Join/results
I have two tables SCHOOLS and STUDENTS They both have a SCHOOLID that can be joined. What I need to see are ALL of the SCHOOLS and fields from the SCHOOLS table and a virtual field telling me if there are ANY STUDENTS that have that SCHOOLID.
Example:
SCHOOLS
SchoolID
School
Active
STUDENTS
name
SchoolID
RESULT Table:
SchoolID Active Used (yes or No)
So the virtual field USED is telling me if there are ANY schools that are in the STUDENTS table.
Then I want to make another query that I can add a where clause to the SchoolID So SAME result be asking "Does SchoolID have any students from the STUDENTS table that have that SchoolID" Then it would list that school (ONE RECORD) SchoolID, School, Active, Used
I have two tables SCHOOLS and STUDENTS They both have a SCHOOLID that can be joined. What I need to see are ALL of the SCHOOLS and fields from the SCHOOLS table and a virtual field telling me if there are ANY STUDENTS that have that SCHOOLID.
Example:
SCHOOLS
SchoolID
School
Active
STUDENTS
name
SchoolID
RESULT Table:
SchoolID Active Used (yes or No)
So the virtual field USED is telling me if there are ANY schools that are in the STUDENTS table.
Then I want to make another query that I can add a where clause to the SchoolID So SAME result be asking "Does SchoolID have any students from the STUDENTS table that have that SchoolID" Then it would list that school (ONE RECORD) SchoolID, School, Active, Used
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For the first query try this.
SELECT Schools.SchoolID, Schools.School, Schools.Active, IIF(Students.SchoolID IS NULL, 'No', 'Yes') AS Used
FROM Schools
LEFT JOIN Students ON Schools.SchoolID = Students.SchoolID;
SELECT Schools.SchoolID, Schools.School, Schools.Active, IIF(Students.SchoolID IS NULL, 'No', 'Yes') AS Used
FROM Schools
LEFT JOIN Students ON Schools.SchoolID = Students.SchoolID;
It is a 2008 SQL server so IIF is not a Function I just tried a direct replacement using CASE and it has a lot of other Syntax errors
This worked (I had a typo on the field name) But it appears to query all of the students rather than just the SCHOOLS
CASE WHEN Students.SchoolID IS NULL THEN 'Yes' ELSE 'No' end
FROM Schools
LEFT JOIN Students ON Schools.SchoolID = Students.SchoolID;
CASE WHEN Students.SchoolID IS NULL THEN 'Yes' ELSE 'No' end
FROM Schools
LEFT JOIN Students ON Schools.SchoolID = Students.SchoolID;
Looking at this again the results are not right. I tried an outer join and it still tries to do a one to many. I just want each school (record) to look through all of the STUDENTS (SchoolD) for it.. if ANY of the STUDENT table has a match .... And there could be 1000's of matches, I just need to know if it was ever used then the single school record say 'Yes' OR 'No' then move to the next record in the SCHOOL table.
LEFT JOIN should work for that.
What exactly is being returned?
Do the no of records returned exceed the no of records in the Schools table?
Have you tried using SELECT DISTINCT?
What exactly is being returned?
Do the no of records returned exceed the no of records in the Schools table?
Have you tried using SELECT DISTINCT?
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