Wykombinowałem takie zapytanie:
SELECT n.id
FROM nodes n
   LEFT JOIN nodeassignments ON n.id = nodeassignments.nodeid
   LEFT JOIN assignments ON nodeassignments.assignmentid=assignments.id
   WHERE (assignments.dateto > unix_timestamp() or assignments.dateto='0' )
   AND assignments.datefrom < unix_timestamp()
   AND assignments.suspended = 0
   AND access = '0'
   AND (SELECT SUM(value) FROM cash WHERE customerid = n.ownerid) >= 0

wykonuje się ładnie i szybko. ale jeśli wrzucę to do update:
UPDATE nodes SET warning=0, access=1 WHERE id IN (
SELECT n.id
FROM nodes n
   LEFT JOIN nodeassignments ON n.id = nodeassignments.nodeid
   LEFT JOIN assignments ON nodeassignments.assignmentid=assignments.id
   WHERE (assignments.dateto > unix_timestamp() or assignments.dateto='0' )
   AND assignments.datefrom < unix_timestamp()
   AND assignments.suspended = 0
   AND access = '0'
   AND (SELECT SUM(value) FROM cash WHERE customerid = n.ownerid) >= 0
)

to mysql krzyczy:
#1093 - You can't specify target table 'nodes' for update in FROM clause

--
Pozdrawiam
Marcin / nicraM