Need one row only returned from INNER JOIN

Question

I would like to return the first row only from an inner join. I have two tables:

TABLE_X |  TABLE_Y
id      |  id   creationdate  xid 
1       |  1    01/01/2011    1
2       |  2    01/01/2011    1
3       |  3    31/12/2010    2
4       |  4    28/12/2010    3

Rows in TABLE Y can have identical creation dates so I am first getting the MAX(creationdate) and then then MAX(id) from this set, for example:

SELECT  a.id,
        c.id,
        d.id,
        e.id,
        d.CREATIONDATE,
        a.REFNUMBER,
        a.DATECREATED,
        a.DESCRIPTION,
        e.CATEGORYCODE,
        e.OUTSTANDINGAM_MONAMT,
        e.PREVPAIDAMOUN_MONAMT,
        e.TOTALINCURRED_MONAMT,
        e.LOSSFROMDATE,
FROM 
TABLE_A a
INNER JOIN TABLE_B b ON (b.id = a.id)
INNER JOIN TABLE_C c ON (c.id = b.id)
INNER JOIN TABLE_D d ON
(
   c.i =
   (
      select
      d.id
      FROM TABLE_D
      WHERE TABLE_D.id = c.id
      AND TABLE_D.id =
      (
         select
         max(id)
         from TABLE_D t1
         where c_id = c.id
         and CREATIONDATE =
         (
            select
            max(CREATIONDATE)
            from TABLE_D t2
            where t2.c_id = t1.c_id
         )
      )
   ) 
)

INNER JOIN TABLE_E e ON
(
   d.i =
   (
      select
      e.d_id
      from TABLE_E
      where d_id = d.id
      AND id =
      (
         select
         max(id)
         from e t1
         where e.d_id = d.id
         and CREATIONDATE =
         (
            select
            max(CREATIONDATE)
            from TABLE_E t2
            where t2.d_id = t1.d_id
         )
      )
   )
)

This works when I call it on it's own but when I add it to an INNER JOIN I am getting a row for each matching row in table Y.

What I want is the latest record by creationdate and id where xid = id from TABLE_X.

Answer 1

Try this query

select *,(
select top 1 creationdate from Table_Y 
where from Table_Y.xId = m.id
order by Table_Y.CreationDate 
) 
from Table_X m

The sub query will pick the top 1 result which have max creationdate and the main query will pick all the records so you have your desired result

Answer 2

This should do it The complex subquery works out the max date for each Y.xid group, and from that, further works out the Max Y_ID (let this represent the key on table Y)

SELECT X.*, Y.*
FROM TABLE_X X
INNER JOIN (
    SELECT t1.xid, Max(t1.Y_id) MaxY_id
    FROM
       (SELECT t2.xid, MAX(t2.CREATIONDATE) MDate
        FROM TABLE_Y t2
        GROUP BY t2.xid) t
    inner join TABLE_Y t1
        on t.xid=t1.xid and t.MDate = t1.CREATIONDATE) MAXY
    ON MAXY.xid = X.ID
INNER JOIN TABLE_Y Y
    ON Y.Y_ID = MAXY.MAXY_ID