je ein Eintrag mit dem höchsten Datum (Group By ?)

[omata]

Vielleicht so...

SQL-Code:

SELECT 'a' AS typ, wp.wsid, wp.thedate, wp.thevalue,
       s.wsid AS ws_id, p.projectid AS project_id
FROM wsprogress wp
INNER JOIN workstep s
  ON wp.wsid = s.wsid
INNER JOIN project p
  ON s.projectid = p.projectid
WHERE p.id = 110
  AND wp.thedate <= :bis_datum
  AND wp.thedate = (SELECT MAX(thedate)
                    FROM wsprogress 
                    WHERE wsid = wp.wsid
                      AND thedate <= :bis_datum)

UNION

SELECT 'b' AS typ, wp.wsid, wp.thedate, wp.thevalue,
       s.wsid AS ws_id, p.projectid AS project_id
FROM wsprogress wp
INNER JOIN workstep s
  ON wp.wsid = s.wsid
INNER JOIN project p
  ON s.projectid = p.projectid
WHERE p.id = 110
  AND wp.thedate = (SELECT MAX(thedate)
                    FROM wsprogress 
                    WHERE wsid = wp.wsid)

Gruss
Thorsten