This seems odd. It's not deciding that it's ambiguous or coming from another datatype for which no implicit cast exists. It knows perfectly well that it wants to convert to text but fails?
postgres=# select 'a'||b from (select 'b' as b) as x; ERROR: failed to find conversion function from unknown to text -- Gregory Stark EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly