Question

Given 3 tables with columns below…

table (columns)

A (a_pk, b_pk, other)

B (b_pk, a_pk, c_pk)

C (c_pk, b_pk, date)

(comment: pk is a primary key, date is a date)

…I’m trying to select…

A.a_pk, A.other, C.date

…with the following restrictions:

max(B.b_pk) group by B.a_pk (only select the maximum of B.b_pk for every A.a_pk)

A.other = ‘something’ (just a WHERE example)

ORDER BY C.date (order by latest dates)

Below is one attempt without success (others looked even more screwed up)

SELECT A.a_pk, A.other, C.date
FROM A, C
WHERE   
 A.other = 'something'
 AND
 A.a_pk IN 
  (
  SELECT max(B.b_pk), B.a_pk, B.c_pk, C.date
  FROM B
  INNER JOINT C ON C.b_pk = B.b_pk
  GROUP BY B.a_kp
  )
ORDER BY C.date DESC

How should it be done?

Answer 1

try

     Select A.a_pk, A.other, C.date
     From A Left Join (B Join C On C.b_pk = B.b_pk)
         On B.a_pk = A.a_pk
             And B.b_pk = 
                 (Select Max(b_pk)
                  From B
                  Where a_pk = A.a_pk)
     Order By C.Date