The following sql statement fails because the column "user_id" does not exist in the users table. =# select user_id from users WHERE username = 'blah'; ERROR: column "user_id" does not exist LINE 1: select user_id from users WHERE username = 'blah...... ^ The following shows a valid statement where I want to delete one user entry from the "map_users_roles" table =# delete from map_users_roles where user_id = (select id from users WHERE username = 'blah'); DELETE 2 If I made a mistake and changed the "id" column to "user_id" then from some the statement executes. =# delete from map_users_roles where user_id = (select user_id from users WHERE username = 'blah'); DELETE 33631 I would have thought that the last statement would fail. Instead it removed all the entries from the table. This is happening because I did not qualify the column names as follows... =# delete from map_users_roles where user_id = (select u.user_id from users as u WHERE username = 'blah'); ERROR: column u.user_id does not exist LINE 1: ...lete from map_users_roles where user_id = (select u.user_id ... Still, this was quite a suprise to me and I would consider this a bug. Thoughts? -- Harry http://www.uklug.co.uk http://www.hjackson.org