Some queries don't work in PostgreSQL

Issue Summary

e.g.
SELECT COUNT(*)
FROM p6_node n
INNER JOIN p6_term_node t
ON t.nid = n.nid
WHERE 1 AND n.type NOT IN ('0','1','0')
AND n.status = 1
AND t.tid = 465;

There exist four queries int the directory_get_nodes_by_term function which contain the statement "WHERE 1". This does not work in PostgreSQL. I've replaced WHERE 1 with WHERE 1=1, which causes the query to not fail. Removing 'WHERE 1' also alleviates this problem. I have not tested the changes on MySQL.