Question

I have the following query

SELECT ID, TestReason
FROM Test as t
INNER JOIN TestResult as tr ON t.ID = tr.TestID

A test can have multiple test results.

The TestResults are A, B, C or D, F.

I need to say for each test, give me the max test result, but the ID’s on the test results have nothing to do with the grade, so I have to use the string.

Here are the tables:

Test

ID    TestReason
int    int

Test Reason

ID    Grade
int   varchar(2)

So basically the highest grade trumps all, so if the test (TestID = 1) contains a test result of A,C,C,D,D I need the 1 record returning like so:

1 A

How would I do this?

Answer 1

Maybe I am missing something but did you try this – since you are using letter grade, then you will use MIN():

select MIN(r.grade), t.test_id
from test t
inner join testresult r
  on t.test_id = r.id
group by t.test_id

See SQL Fiddle with Demo

Or you can use row_number():

select grade, test_id
from
(
  select r.grade, t.test_id,
    row_number() over(partition by t.id 
                      order by grade) rn
  from test t
  inner join testresult r
    on t.test_id = r.id
) x
where rn = 1

See SQL Fiddle with Demo