SQL-Problem mal wieder

[Grolle]

SQL-Code:

Tree
(ID, NAME, PARENT)
(6, 'Kunden', 0);
(8, 'Behörden', 0);
(9, 'Banken', 0);
(10, 'Intern', 6);

Tree2Contact
(ID, TREE_ID, CONTACT_ID)
(1, 8, 22);
(2, 6, 25);
(3, 6, 22);

SQL-Code:

SELECT distinct(tree.name) as name, tree.id as id, tree2contact.contact_id as contact_id  from tree left join tree2contact on tree.id=tree2contact.tree_id
Where ((tree2contact.contact_id=25) or (tree2contact.contact_id is Null)) and tree.parent=0 order by tree.name

soll:
('Banken', 9, NULL);
('Behörden', 8, NULL);
('Kunden', 6, 25);
ist:
('Banken', 9, NULL);
('Kunden', 6, 25);

bei:

SQL-Code:

SELECT distinct(tree.name) as name, tree.id as id, tree2contact.contact_id as contact_id  from tree left join tree2contact on tree.id=tree2contact.tree_id
Where ((tree2contact.contact_id=22) or (tree2contact.contact_id is Null)) and tree.parent=0 order by tree.name

soll:
('Banken', 9, NULL);
('Behörden', 8, 22);
('Kunden', 6, 22);
und ist auch so. (Teste mit IBExpert)

viele Grüße ...